Date: Mon, 6 Dec 93 11:41:18 GMT
From: Peter Aslan
A recent article in Classic Bike December 93 states:
AMAL CARBS: STILL BREATHING AMAL of Birmingham,
(England) has sold its motorcycle carburettor business. Britan's leading
manufacturer of instruments for two-wheelers since the 1920s, is to concentrate
on non-automotive industrial products. Buyer; Grosvenor Works will continue
manufacture of the latest Concentric carburettors at its north London plant,
which also makes Zenith car instruments.
The company, which was a major contractor for Amal, is on (081) 808 7782.
Fifteen staff at Amal, which is owned by IMI Group, will retire early, or be redeployed.
Here in England we used to call it 'downsizing', the latest buzzword is 'rightsizing'.
The good news is, Amal Carb manufacturing continues England. I assume they will continue with Mk I and Mk II concentrics, they haven't produced monoblocks for quite a few years, people have been known to switch from monoblock to concentric however.
Date: Fri, 3 Dec 1993 09:58:05 -0800
From: Alastair Young.
Peter Aslan said:
>By the way, Amal still produce carbs in the
U.K. They seem to have sliped by in the
>night and escaped the demise of the rest of
the sub manufacturs. You can still
>purchase concentric parts in the uk, 28, 30
and 32mm. Bodys cost around $25.00
>Throttle Slides about $8.00. Or about $55.00
for a complete carb, (Mk I) or $85.00
>(mkII).
I believe they are actually made by "IMI-Amal" in Spain. Unless prices have dropped phenomenally in the last 4 years readers should substitute british pound signs for the $ signs in the prices above. I bought a new Mk 1.5 for 55 pounds 4 years ago. Users of monoblocs, separate float carbs or Mk-1 concentrics: If you are opting for a new carb rather than refurbishing the old, I recommend the Mk 1.5. It has a much nicer choke mechanism.
My NH has been a first kick starter ever since, even at sub-zero temperatures. The choke comes in two forms: lever or cable. I opted for lever as it is one less cable to worry about (throttle, choke, brake, ignition advance, valve-lifter and clutch was a real pain, I'm now down to the essential three)
5.2 The Mk1, Mk1.5 and Mk2 Amal Concentric.
Date: Wed, 8 Dec 1993 10:57:10 -0800
From: Alastair Young
>Peter Aslan said:
>The good news is, Amal Carb manufacturing continues
England. I assume they will
>continue with Mk I and Mk II concentrics, they
haven't produced momoblocks for
>quite a few years, people have been known to
switch from momoblock to concentric
>however. Dont know what a MK 1.5 is.
The Mk 1 has a two bolt flange fixing and a tickler. The Mk II has a round clamp type fixing and a fuel injector type choke. The MK 1.5 is effectively a Mk II with a Mk 1 flange. They may have renamed the Mk 1.5 to Mk I and discontinued the "real" Mk 1 carbs. I suspect that new manufacture of carbs with ticklers may be illegal for safety reasons.
I first heard of the Mk 1.5 when the Harris Bonneville's came out as that is what they were fitted with. I think that this hybrid may have been originally produced for that application. First kick starting with no leaks, dribbles, tickles, air-valves....joy!
5.3 Converting to the MK2 Amal Concentric Carburetter.
Date: Tue, 19 Apr 94 10:10:11 EDT
Some of the Brit-Iron Commandos (Roy Armstrong,
Pete Serrino) have MK2 Amals installed. Since a pair of new MK2 carbs can
be bought for 140 quid ($210 US) from Fair Spares U.K. with another $10
for a dual manifold, I am wondering if boring and sleeving my MK1's is
worth the savings.
The machining costs from $110 US to $140 depending
on who does it.
Question: do the Mk2s require different rubber
connectors to the air filter front plate? Do they require a different air
filter(s)? I've seen a single Mk2 replace dual Mk1's, would dual Mk2's
be overkill? Is the conversion worth the effort?
Date: Tue, 19 Apr 1994 10:48:12 -0500 (EST)
John Pinkham writes:
So what's the difference between the MKl and MKll,
or for that matter the MKl 1/2?
Also, I saw an article on replacing the tickler
with a larger button for easier use. It looks pretty good. Has anyone tried
the conversion?
Date: Tue, 19 Apr 1994 12:50:42 -0500 (EST)
Chuck writes:
The differences are significant. The MKII (square
bodies) were made of cast aluminum instead of pot metal. The aluminum slides
are coated to reduce wear. They also feature a true pilot jet for easy
low speed tuning.
The MK 1 1/2's or MKI A's (?) are MK I's(concentrics)
with the MKII enrichment circuit replacing the choke slide. I have tried
dual Mikuni's as well as the dual MKII's. If I had it to do over again
I would have the concentrics resleeved and fit the MKII pilot jet to the
body.
My Norton always had the best top end with the
concentrics. Resleeving should eliminate the erratic idle and the pilot
jet should compensate for richness that some people experience aftee resleeving.
Date: Tue, 19 Apr 1994 09:51:23 -0800
Chuck Stringer wrote:
I think it goes like this:
Generally you can use a Mk1 1/2 as a straight
replacement for Mk1, Monobloc or pre-monobloc types. I replaced my knackered
monobloc with a Mk 1 1/2. Best $55 I ever spent.
Date: Tue, 19 Apr 94 12:38:00 -0600
Whatta bunch of wimps. Hell I kin remember back
in '01 when we did'nt have the fancy carbs you young whippersnappers are
whinning about. Try a real mans carb, a surface carb. This one coaxes a
airstream over a pool of gas in the hope that enough gas would evaporate
into the stream and eventually flow through the 'atmospheric' inlet valve
and maybe the vibrator controlled ignition would ignite the maybe rich
or lean enough fuel air mixture.
When I look at very old motorcycles, it is amazing
that they were considered much better methods of transportation that horse
and buggy. Each year they just get better. Having ridden some bike built
in the 1910 to 1920 range, I am truely thankful for the many modern features
of my 1947 Indian Chief
Date: Tue, 19 Apr 1994 12:06:33 -0800
Your Name Here wrote:
Ah yes, that went with the poppet inlet valve.
The valve was on a very weak spring and the vacuum in the cylinder opened
it and the compression pushed it closed. You ounly had one tappet to worry
about! Oh, and don't forget those leather belt drives...
Date: Tue, 19 Apr 94 14:20:31 CDT
> PS Surface carb, heck we just dribbled gas from
a hose into the intake!!
I've seen a Wal Phillips "fuel injector" that
came with a pile of Enfield bits that was just that (as far as I could
tell). The linkage twiddled two butterflys that were set with a differential
between them. The fuel hose went in the top, with some form of flow control
(a rotating V slot?) working off a third bell crank between them.
There were adds for it in CYCLE in the late 60's,
and I've held one in my hand. Anybody have any more on these?
Date: Tue, 19 Apr 94 14:21:42 CDT
Andrew Wolf states:
Yow! This sounds like the fiberglass arguments
I hear THESE days. "How can you ride that old stuff?" "Don'tcha get sick
of gas dribbling down the side of the carb?" Guess OLD is relative.
Date: Tue, 19 Apr 1994 12:42:25 -0800
Chuck Kichline wrote:
I read an article once that had one of these fitted
to a 500 VH Ariel single. Along with twin plugs and some porting, it would
apparently do 125mph. On a not very related thread, there are some Dutch
guys who have got hold of some late 50's plans from the Ariel works for
an Ariel 1000cc V-twin, and they've gone and built the thing.
It uses 2 VH barrels and heads and has a the timing
cover from the single. Wet sump, uses the generator as an electric start
and produces 78bhp at the crankshaft. Not only that, but it fits into the
regular Ariel swingarm frame. 78bhp in 1958.....no wonder BSA closed them
down. Did BSA have anything at the time that could compete with that?
Date: Wed, 20 Apr 94 08:50:19 +1000
John asked:
I have the twin carb set-up. I did it around ten
years ago when MK2's were new.
The advantage of the MK2 choke and the hope that
they would not wear as much as the MK1's were main factors in making the
change. The old air box had to be removed and put on the shelf. Some suitable
air filters fitted to each carb took some time to find but there wasn't
much available ten years ago.
I believe you can get other brands of filters
now. The old MK1's that I removed were totally stuffed, hence there seemed
to be a great improvement in performance with the fitting of the MK2's.
After ten years of reliable performance I am now thinking of fitting MK1's
back on again. This is mainly for originality and the fact that re sleaving
is more common now.
I also have a box of MK1's that I have accumulated
over the years and it is a lot cheaper to re-sleave them than purchase
new carbs.
Date: Wed, 20 Apr 1994 08:56:48 +0800
I've read some interesting responses re Amals/sliding/tickling
and it appears that it would be silly to change from one to the other when
you are happy with the way your bike is starting. One thing that annoys
me about the MkIIs on my 81 Bonny is my lack of success in finding airfilters
that fit over the mouths of each carby so I can get rid of the bloody awful
looking air box, which I admit works perfectly. But I have looked longingly
at those bikes with the MkI carbs and those neat looking unipods.
Date: Tue, 19 Apr 94 21:50:00 PDT
I've never had problems or concerns with the choke
lever on any of my Nortons. _My_ big gripe about the Amals was the fact
that they would get hot, distort, and then jam the throttle wide open.
No amount of heat-washers, air ducting or auxiliary fans ever helped. Therefore,
MacBeth will have twin flat-slide Mikunis and a curse on everyone who whines
that they're not stock :-)
Date: Wed, 20 Apr 94 02:37:01 EDT
Ok, all this discussion of Nortons running Amal
Mark I's vs. Mark II's etc. has lit a fire under my ass: my beloved and
once trusty Norton has been languishing in boxes in my garage for the last
year or so - ever since I pulled the barrels and looked down at the tragic
sight of a flat cam sitting there in my cases.
I decided at that point that since I didn't want
to put it together half-assed, I would wait until I had enough dough to
put it together the 'right way.' Depending on my mood and the relative
position of the zodiac the 'right way' appears to range from 'all-out-badass-cafe-racer
with upside down GSXR front end' to complete and total classic restoration.
Whatever. Even if the reality is going to be somewhere in the middle (a
powerful but fairly reliable engine in a comfortable chasis with modern
electrics), I will still need a fair amount of $$ to put it together properly.
But all this talk of Nortons has got me going, and despite the fact that
I thoroughly enjoy riding my Guzzi LeMans, the fact remains that Its Just
Not The Same.
Somehow no matter how interested I may be in Guzzi
stuff, there's just not the passion I feel for my beloved 'Betsy.' The
old 'wife vs. The mistress' dilemma i guess. Anyway I'll get to the point:
I'm somewhat interested in trying to put my Commando motor into a Featherbed
frame. I was never really able to get that slightly 'wandering' feeling
to totally go away even after tight shimming and new swing arm bushings.
She felt OK except in really hard turns, perhaps this was because she's
a 750 - with that twitchy front end and the un-braced swing arm - I dont
really know.
Does anyone out there have any experience doing
serious upgrades to the Commando frame (DDodge?) - what can you recommend?
I have also heard of someone who spaced out the isolastics with solid metal
washers to effectively make it rigid mounted - it was said that this possibly
fictional person also had the engine rebalanced along the lines of an Atlas
to compansate for the vibration... Blah Blah Blah.
I could go on and on, but I won't. If anyone has
any featherbed frames they want to part with let me know - also I'm looking
for some other random spares: an 850 Mark III swing arm and disk rear brake
assembly, some 18 in. Borrianni alloy rims, 850 isolastics, Carrillo rods,
etc. I know how to get all these things through all the usual channels
- what I need is a few 'bargains' cause I'm poor.
Date: Wed, 20 Apr 94 08:56:09 CDT
Bennett writes:
In a private email, John Kula writes:
Bennett, meet John. John meet Bennett. There have
been serveral examples of Commando motors in featherbed frames, but none
that I have seen that kept the isolastics (they all used the atlas style
mounting).
One obvious problem is the clearance at the back
of the gearbox where the Commando swingarm attaches to the cradle fouling
the featherbed swingarm. Mounting points for the isolastics might also
be a problem. Sounds like it is time for an experiment. One thing I will
say, the Commando frame is *much* lighter than the featherbed.
Date: Wed, 20 Apr 1994 10:51:52 -0500 (EST)
Bennett writes:
I'm a bit confused as to why everyone is so hot
to tear classics apart to build hybrids. Wouldn't the end product be worth
considerably less than either or both of the original bikes restored? Were
the Atlas' that bad?
5.3.1 Amal
Carb Configurations on The Commando.
Date: Wed, 25 Jan 95 14:47:46 GMT
Further to my last post on Amals on Commandos,
I would like to add:
To Start with, this is how it came from the factory:
Commando 850 Mk2a Manufactured April 1974 originally
as a High Rider
Now, if you have a Commando, please post your
Amal Carb configuration/Settings. Provide the same info as above or use
this mail as a template. I would really like to find out what other people
are running.
Also, we could start the same thing for Triumphs.
Owners of Minuki do not need to apply.
P.S. I'm sure the needle position starts at 1,
(top) with 3 the (bottom). although we usually say Raise or Drop the needle
a notch and dont refer to position. If the needle goes up, more petrol
goes in (Ritcher) if the needle goes down, less petrol goes in (leaner).
Oh, raising and lowering is relative to the throttle slide, thus if its
in pos 2, (middle) position 1 (top) lowers the needle and reduces the petrol
content of the mixture.
Date: Sun, 2 Oct 1994 20:05:10 -0700 (PDT)
Better late than never:
Date: Mon, 3 Oct 94 09:03:49 BST
Nancy, firstly thanks for posting this stuff.
I for one find it really interesting looking at other Commando carb setup
information, and I feel it gets us all 'one step closer' to sorting out
a lot of carb problems.
It's unfortunate, therefore that yours is still
only the third set of Amal information posted since my request, ah well.
Whats supprising is the number of 850's with Sectioned
Spray tubes out there, I thought it was kinda special. Further to your
post, could you include the Engine No and date of manufacture, this information
is stamped on the metal plate fixed to the headstock behind the headlamp.
I am also particularly interested in the Throttle
Number, (probably a 3 or 3 1/2), its stamped on the top of the throttle
slides. And also, what is a 'contis' ??
Please let us know if the bikes running ok, and
if not any problems you feel may be related to the carbs, poor idle, fowled
plugs etc. Thanks in advance, and a gentle reminder to all other Commando
owners on the list to post the same information for the benifit of us all.
Date: Mon, 3 Oct 1994 12:08:35 +0800
81 Bonneville
Tank and filter box have to come off to clean
them but once thats done they are a 'piece of piss' (as we say down here)
to dismantle and clean. Only complaint about MkIIs is that you cant get
one of those funky Unipod air filters to fit over the mouth. They probably
do make a larger size but then frame gets in the way (carbs point straight
back not slightly to sides as I have noticed on some models).
Ugly plastic airfilter box set up is my only gripe
about a truly beautiful motorcycle. She idles nicely at about 800 with
just the occaisional hic on right hand side (try to eradicate it from time
to time - end up saying after 30 mins fiddling f*@k it lets go riding).
Left hand side keaps time like Charlie Watts.
Date: 3 Oct 1994 09:04:51 U
My Norton's specs, As per Captain Norton's request:
I'm considering slides one size down/up, but I
guess that means that I'll have to get them resleeved too.
Date: Tue, 4 Oct 1994 17:14:27 -0700 (PDT)
>>Further to your post, could you include the
Engine No and date of manufacture,
Engine 302540, manufacture date somewhere between
4-6/73. 3 1/2 slides Conti mufflers. Tried reverse cone and seemed about
the same as far as correct tune goes.
The significant difference for my carbs was the
.105 jets post resleeve. Prior to the resleeve I had been running .106
with the needle in the top groove. It ran very rich after resleeving, and
I tried N8Y plugs which seemed to prevent loading up around town. But it
still wasn't good enough and the .105s made the difference.
Seems there are a lot of folks who face this problem
once they install their redone carbs.
Date: Wed, 25 Jan 95 14:48:08 GMT
So far we have 3 responces to the request for
Amal configurations/setups, and one of thoes is mine. I thought the number
stamped on the carbs would be the same on both carbs, I'll now have to
go out the garage and check.
The preliminary results are: Commandos run better
with a throttle slide one size smaller than originally fitted.
Could this be the result of modern fuels ?
Note on 4 id ring needles: As far as I know, the
4 id ring needle is only used with the sectioned spray tube. And someone
asked, what's a spray tube ? Well... If we start with the throttle slide,
the large cylinderical bit the throttle cable is attached to, the bit that
goes up and down when you twist the throttle on the handlebar. The needle
is fixed to the throttle slide, on amal Mk1 carbs, the needle is held with
a brass clip which fits into one of three groves in the needle.
The clip is held against the throttle slide by
the throttle slide return spring. When assembled, the needle goes into
the base of the carb, into the needle jet. If you look down into the carb
when the top is off and view the top of the needle jet you will see a brass
thing poking up into the carb body arround the needle jet, this is the
spray tube.
A brass tube which rases the level at which the
fuel enters the airstreem.
The spray tube can be removed by carefully tapping
the thing out from above, after removing the needle and main jet and the
jet holder. Once removed, the spray tube is the shape of a top hat with
no top to the hat, the bottom being a kherled section which provides an
interferance fit which holds it in place, the sides being the tube.
A sectioned Spray tube is a tube where one half
of the tube which projects into the airstreem has been removed. A sectioned
spray tube is installed with the cut away positioned towards the engine.
Note on idle jets: The Mk1 Amal has provision
for an idle jet, only one should not be fitted. It locates on the underside
of the carb body, its purpose is to restrict, (govern) the amount of fuel
passing into the idle mixture curcuit. The idle curcuit takes in air from
a small hole bellow the main air intake, there are actually two holes but
one is blanked off. The blanked off hole leads to a drilled hole inside
the carb, above the float chamber, which takes the idle jet. As far as
I remember, the air component of the idle circuit is the one which is regulated
with the idle mixture screw on the outside of the carb body. Both components
enter the airstreem through two tiny holes after the main jet and spray
tubes.
You really need to look at a carb body for all
of this to become clear.
Additional note: the thredded hole which takes
the idle jet also appears as a sleved hole on some carbs I have seen. And
now, back to the point: I believe such idle jets are only used for two
stroke applications with the Amal Mk 1.
Date: Thu, 30 Jun 94 09:29:52
I bought a 72 Bonneville a couple of years ago
and have been slowly improving it. This past winter I rebuilt the carbs.
When I took them apart I found the left carb had a 190 main jet and the
right carb a 180.
Upon checking the original factory parts manual
I found it specified 190 main jets for the T120R Bonneville, so I put new
190s in both carbs. Since then I have been having misfire problems from
about one-quarter to one-half throttle, usually in the 2500 to 3500 rpm
range, and it tends to be worse while accelerating.
Plug readings show the bike is running rich. I
have analyzed the bike to death and cannot find the cause of the problem.
It is not the needles, which I assumed at first. I have them set at the
weakest setting now, the top groove, which is also the factory specified
setting.
The problem does not appear to be electrical so
far as I can determine, which leaves carburation. Last night I noticed
in the original workshop manual that it specifies 180 main jets for all
dual carb 650s in 1972, i.e. a contradictionn with the parts manual which
I followed in installing 190s.
So I went to J.R. Peters' Bonnie: The Development
History which has specs charts for all years and models of the Bonneville.
His book says 180 for the T120 (UK model) and 190 for the T120R (US export
model). Mine is a T120R, so the 190s I put in should be all right, except
that Peters book contradicts the workshop manual. (Incidentally, the parts
manual I have, which was presumably for North America, doesn't even mention
the T120 just the T120R).
Does anyone have any idea what the proper main
jet size is?
Do you think this could be the cause of the overly
rich mixture and misfire problems I'm having?
Personally, I'm dubious that main jet size (especially
such a small difference as 180 to 190) would affect mixture and misfire
problems in the one-quarter to one-half throttle range, where the mixture
is governed by the needle and not the main jet. However, since the needle
seats into the jet, and a smaller jet size would mean less gas flow, maybe????
Anybody out there got any brilliant advice on
this?
Date: Thu, 30 Jun 94 11:22:02 -0600
Bob writes:
Rules:
1. They are all worn out Usually I have my worn
carbs bored out by Lunds.
2. The needle JET is worn. You cannot imagine
how many carbs have worn needle jets, its cheap and it is likely the cause
of your rich running. I have often cheaply fixed the anals with NEW needle
jets
3. Slide cutaway is WRONG likely a 3 1/2 is the
usual one. Before you spend much replace the NEEDLE JETS, no you will NOT
be able to determine if they are worn, however the improvement will be
so noticeable that you will be Amazed
Date: Thu, 30 Jun 1994 10:56:00 -0700 (PDT)
Bob Cram writes:
Somehow this questions has a familiar ring to
it. Maybe it is one of those elemental questions, like why is there air?
Your experience sounds like mine, although I have noted that a misfire
or lumpiness at closer to quarter throttle, and it tends to diminish if
I am accelerating.
What I found is that the idle mixture screw has
an infuence up to about quarter to third throttle, despite all the good
references that say it affects idle only. This may be a compromise setting
which is trying to deal with wear in the slides. Good luck.
Date: Thu, 30 Jun 94 13:19:41 CDT
When I dragged my '68 Lightning out of the garage
(1985-90) I was plagued with rich running - especially at 45-65 mph; missing
out, black plugs, the works! I thought it would be a leaky float or a sticky
float needle, since the bike had always been spot on before.
After much frustration, Steve Tuffs steered me
into needle jets and needles a step leaner than stock and the "new style"
(whatever that was).
That solved the problem. Steve mentioned that
the gas had changed and the flow properties were different. I could believe
that. But if so, then wouldn't all the old published specs be incorrect?
Anybody with a view on fuels and jetting willing to share some opinions?
Date: Thu, 30 Jun 94 14:41:33 CDT
Didn't the octane ratings change in the mid 70's
(down in rating by 2 or 3 points)? I understood that it was the testing
method (something about Research Octane Number) that changed and not the
actual fuel. If so, we shouldn't need the unobtanium fuel. Gotta be a Petroleum
Engineer out there somewhere!
Date: Thu, 30 Jun 94 21:37:52 BST
> Didn't the octane ratings change in the mid
70's (down in rating by
The octane rating did go down, leaded fuel was
higher octane than regular unleaded. When I first got my Trident (first
britbike, can't believe I got another one after that intro) I was horrified
to find it wanted 98 octane leaded. Turns out a british octane is different
than an american octane, I think the british use Whitworth octanes. I run
most of my bikes on 89, every now and then I toss in some 92 or 93 when
it's convenient. No problems.
Date: Fri, 01 Jul 1994 07:26:33 -0500 (EST)
Chuck writes:
This past year a member of our Norton club (NY
Norton owners) had his carbs resleeved and replaced the needles and needle
jets.
The needles he received were shorter than his
originals.
After repeated fouling he finally discovered he
was sent "Triumph" needles. I assume these are the "old" style for Triumph
owners. When he replaced them with the original longer style everthing
cleared up.
BTW he said the bike ran like a bat out of hell
for about three miles before loading up and stalling out with the short
needles.
>Anybody with a view on fuels and jetting willing
to share some opinions?
I am convinced the newer fuels burn richer than
the gasoline sold when our bikes were new. It seems my Norton is more sensitive
to this than my other bikes though. It also varies quite a bit by region.
A few years ago at the Norton National at Laconia,
New Hampshire most everyone was complaining of fouled plugs. (<1000
foot elevation). Most of us had ridden in and had no problems until after
gassing up there. Things cleared up on the way home after a couple of tank
fulls.
Date: Fri, 1 Jul 94 8:46:24 PDT
John Knobel writes:
Would Amal Mk IIs do the trick? Mk 1.5's? I'd
suspect the carbs. To quote Andrew Wolf: "Someone asked how to tell if
a Amal carb is worn, well if it is the original, has not been resleeved,
then it is WORN."
I have a Mikuni carb on my Norton. It'll idle
smoothly as long as I let it run. John Pinkham recently had his Amals resleeved
and I think he has a smooth idle as well. You might want to consider having
your carbs resleeved at Lund's...
Date: 1 Jul 1994 10:54:23 -0500
With all the discussion of jetting problems with
the Amals - is there ever a cure?
Would Amal Mk IIs do the trick?
Date: Fri, 1 Jul 94 13:31 EDT
> I'd suspect the carbs. To quote Andrew Wolf:
"Someone asked how to tell if
I'd like to amend this: "If it's not brand new,
it's worn". The design of the Amals is fine, they're just made of shit
metal. The wear isn't just the slide, the carb body wears too, and you
can never tell what some previous owner did - a lot of people will replace
just the slide when they can see that the slide is worn, which doesn't
help much.
I've been going through all our bikes having all
the amals re-sleeved as I can afford it, some needed it more than others
but they all benefitted from it. Oh yeah, new needles too, they're cheap
enough that it's good insurance. They generally don't show the wear, so
unless you know what to look for (I don't) they look ok.
Date: Mon, 4 Jul 94 12:57:56
My original question about whether switching my
72 Bonnie from 190 to 180 main jets would solve my misfire problem has
sparked a lot of discussion. Anyway, I thought you'd like to know that
I made the switch on the weekend and experienced a very noticeable improvement.
The mixture is leaner now and plug readings are
better. However, it still misfires a bit, but over a narrower throttle
range and not as badly. Although the books say main jets aren't supposed
to have an influence until three-quarter throttle, it obviously made a
difference in my case in the one-eighth to one-half throttle range.
I presume that this is because all fuel goes through
the main jet to get to the needle jet. Thus the quantity of fuel flow is
directly affected by main jet size even at lower throttle openings.
What the books should say is that the main jet
size is the sole influence on fuel flow above three-quarter throttle, and
below that it is a factor along with throttle cutaway, needle jet size,
needle size, etc.
Does that make sense?
Re the question that arose last week about different
needle jets and needles in the more recent years, Triumph did make a change
about 1969. I have more accurate information at home and will try to remember
to bring it tomorrow. Essentially, though, the more modern needle jets
had an extra very small cross-sectional horizontal hole through them giving
better flow characteristics.
Older Triumphs can be improved by using the newer
system, or so the source I have claims. However, it is crucial not to mix
parts, such as putting an old style needle with a new style needle jet.
Anyway, I'll send the accurate details tomorrow. For those of you with
copies, it is in Nicholson's "Modern Motorcycle Mechanics," a great out-of-print
book for British bike fans, but hard to get hold of now.
Date: Tue, 5 Jul 1994 10:20:17 +0200 (METDST)
My 'box says that on July 4., Bob Cram wrote:
From my technical viewpoint there are some truth
in your words, but only some.
The fuel will be restricted and hence metered
by the part of the carb that provides the biggest resistance. As the main
jet can deliver enough fuel for full throttle riding, it will not restrict
fuel very much at smaller throttle openings. But this would depend on all
other things being equal, which they aren't - ie. needle position in jet
not constant to take one example. Pressures around needle being different
in different running modes etc.
So much for theory (and it has been some time
since I studied these things, so the reasoning may be a bit blurry). My
practical experience says that the original wording is not far from truth.
Reducing main jet size should lead to other problems at higher speeds,
lean and hot running.
How does the Triumph perform after the change?
I'd suspect you'd have expended some go, and would think of looking for
another reason for the misfire.
PS. Does my '37 Matchless mod. X run. Yup. Trouble
free? No. Big misfire the other day, lost one cylinder 80 percent, nearly
didn't make it home. Head scratching. Think think. Notice lots of sparks
at one set of points, no sparks at the other. (Two sets because of homemade
ignition, superior to magneto in all respects). More think. Buy new condensers.
Take old ones off, find wire broken from vibration. Weld old wire to old
condenser. Good as new. Now have extra condensers!
Date: Tue, 5 Jul 94 09:13:30
Rolf Clausen writes, in part:
How does the Triumph perform after the change?
I agree, in theory, but as so often happens theory
and reality don't seem to match. A real Amal expert could probably figure
this one out, and maybe someone will do that for us. One piece of information
in my original message about this is that different Triumph factory sources
gave different specs for this year for the Bonneville. Some said 190 for
the main jet; some said some 180; some listed both.
Date: Tue, 5 Jul 1994 17:28:11 +0200 (METDST)
Just a small snip from Bob Cram's writings:
I'd say there shouldn't be such a big difference
between a 180 and a 190 jet. In my experience the *correct* jet is a compromise,
and sometimes the smaller jet would be better than the other or just the
opposite.
A worn 180 could be a 191 or maybe even 195 if
the fuel contains a lot of grindy stuff. If your air filter is dirty this
can outshadow such a small difference in jet sizes. You do have an air
filter, don't you?
Date: Tue, 5 Jul 94 10:50:34
Thanks Rolf: The 190 main jets I was using were
brand new.
The 180s, which I got from a friend, were used,
hard to say how used, but I gave them a good cleaning. The difference may
be small, but it was visible to the naked eye that the used 180s were still
smaller than the new 190s.
Interestingly, when I took out the old jets this
past winter, I found that the previous owner had a 180 in the right carb
and a 190 in the left carb. The left carb is only a couple of years old.
The right one is older, probably original, but has all new internals. It
wasn't rebored, but there seems to be a tight fit between it and the throttle
slide.
Yes, I do have air filters, and they are both
brand new. Believe me, I've been puzzling over this for awhile and trying
everything. The suggestion I got from John Pinkham regarding the Triumph
Service Bulletin of 1973 and float levels looks very promising.
Date: Mon, 4 Jul 94 19:12:55
I was able to get the information a bit earlier
than promised regarding the "new style" needle jets. It appears that this
was common to all Amals (or at least Mark 1 and probably 1.5 concentrics),
and not just Triumphs.
The passage about this is in a chapter on "Servicing
Common Components--British Models" in the seventh edition (1974) of "Modern
Motorcyle Mechanics" by J.B. Nicholson. The Nicholson brothers ran a mainly
British motorcycle shop in Saskatoon, Canada from the mid-30s to mid-70s,
and their book was the standard textbook in Canada for motorcycle mechanics
in Canada in that period.
It says: "A cross hole through the hexagon portion
of the needle jet was introduced in 1969 and this feature applies to most
'69 and later units. A different throttle needle is used with the cross-hole
needle jet.
Earlier carburetors can be converted to the new
specifications to advantage. The following parts are required: No. 622/124
Needle, No. 622/122 Needle Jet and No. 622/128 Jet holder. When servicing
it is essential that the throttle needle and jet are matched and that only
throttle needle No. 622/124 is used on units with the cross-hole through
the needle jet hexagon."
Date: Tue, 5 Jul 1994 08:05:25 CST
[edit out various carb trouble]
Just thought it might be interesting to note that
after Saskatoon the Nicholson brothers (Bernie and ?) moved thier business
to Calgary, Alberta where they ran almost strictly mail order until a year
or two ago when they closed up shop and retired.
The book "Modern Motorcycle Mechanics" is still
available through British Cycle Supply Co. in Wolfsville, Nova Scotia (see
ad in any old bike mag). Just out of curiosity, where are all the Brit
bike dealers in Canada disappearing to?
Date: Fri, 1 Jul 1994 16:48:58 -0600 (CST)
Howdy, Another Amal problem is nicks on the sides
of the needles.
As we all know (if you dont, reach in and wiggle
it!) the needles shake back and forth. Well, if you have a bad enough nick
(guess what, bad enough here is also known as very little) it may hang
up when you let up on the throttle, causing it to idle high.
So you turn out the idle screw, and suddenly it
won't idle! So examine those needles! I had another problem after I'd had
a carb stick (the bike sat for a few days in the cold). What happened was
that when it came unstuck, the needle tip missed the jet and was forced
(along with that c shaped clip) up into the spring. This cracked the clip
right where the needle goes. The crack was impossible to see, until a friend
of mine said "oh I gotta replace my clip becasue my carb got stuck..."
and when I looked, there's a crack! This can be none too good for holding
the needle in place.
Date: Mon, 18 Apr 1994 10:10:03 -0700
Does anyone actually use the air slides in their
amal carbs?
I just installed some in a effort to be more original,
and I can't seem to get them to go all the way up, so that no part is visible
with the throttle wide open. I wonder if this is normal, because I've never
stared down the carb throats of a bike that had them installed before.
Just wondering,
Date: Mon, 18 Apr 94 12:55:47 -0600
Does anyone actually use the air slides in their
amal carbs?
Well I do, on my Spitfire, I have a 389 and a
689 with the large tank. and air cleaners. My fingers are not that long,
nor do they have enough joints to get to the ticklers. So I installed the
air slides and they work very well, I can start my bike from cold and not
have gasoline soaked fingers to boot.
Hell I like it so well I gonna install a set on
the Bonneville. The local triumph expert says they were all removed because
the operation wasn't intuitive (turn the lever cw to open the slides and
ccw to 'close' them) and the cables would break and allow the slides to
drop and cause very rich running. Also not real good on very cold mornings.
Yes my air slides do go all of the way to the top.
To check yours, just grab the cable above the
carb and pull, The slide should go to the top. If it doesn't, likely it
is binding in the carb. If it does then you gots to sort out the cable
problems. If you have a single carb then you have it simple and this usually
means the effective length of the cable is too long. (effective length
is inner cable - outer cable) This can be shortened by using a clipper
and soldering iron, Unsolder the tip, slide it down the cable, tin the
cable at the correct length, clip the cable, then resolder. I usually solder
at the handlebar end so that a poorly executed solder joint will merely
be inconvinient not catastrophic.
The dual carb unit has a junction box and this
unit makes it a bit more difficult. Check to see if the free play is on
the dual cable end or the single cable end. If the dual end has freeplay
and the single end has none, then shorten the effective lengths of the
dual cables. If this helps you then you are for ever indebted to me.
Date: Mon, 18 Apr 1994 13:21:28 +0000
Andrew Wolf writes:
I just had a cable break on the Norton...yep,
the slides drop down and make the bike run rich--not a good thing.
>PS the rumor is that Cindy Grant installed one
on her Triumph I painted
My BSA is!!!!!!!!! Yes, I do have an air slide
on the Triumph...the truth of the matter is, I insisted installing the
air slide for purely cosmetic reasons (I love looks of the choke lever)...I'll
probably never use the choke. And, no, the Triumph is not running yet.
I am currently serving out a term in Norton Hell...held captive by the
Lucas gods.
As of today, I formally give up on the Norton.
If she doesn't want to run...fine, she can just sit in the garage for a
while. I've had enough of Ms. Norton...it's time to get back to the Triumph.
Date: Mon, 18 Apr 1994 16:48:20 -0800
At 10:10 AM 4/18/94 -0700, Robert D. Burget wrote:
Air slides are a waste of time. You only use them
at starting and can get the same "rich mixture" choke effect by excess
tickling (though this is a fire hazard) and do away with that extra control
cable. Newer amals got real choke levers.
Date: Tue, 19 Apr 1994 08:47:22 +0800
I am sorry but I am not sure what air slides are.
I have a pair of MkII Amals and don't know what terms like 'tickling the
carbies'.
When I start I just move the choke lever and the
handle bars to half and open the taps after its fired up.
Date: Tue, 19 Apr 94 11:24:59 +1000
Bob asked:
Yes! I recently fitted them to my BSA A70 Lightning.
Prior to fitting if the bike was left for a few days it was a pig to start
from cold. Now it is no problem at all.
My Commando has MK2 Anals, without using the chokes
it is also a pig to start.
Date: Tue, 19 Apr 94 00:12:45 CDT
>Air slides are a waste of time. You only use
them at starting and can get the same
Newer amals got real choke levers. I always thought
this was so, until I replaced a bodged DelOrto on a 250cc Salami Slicer
Guzzi with a Concentric. I had trouble enough routing the cable to the
non stock location so I left out the choke and plugged the hole.
The bike is incredably coldblooded. To start it
you flood it until gas runs out the mouth of the carb. Then it starts first
kick. But it will die unless you either hold your hand over the bell or
hold down the tickler, until it is really warm. Then it runs fine, with
a nice brown plug. I don't know why this is. But I have two guesses.
1) The bike comes from a Mediteranian From: espen@itekiris.kjemi.unit.no (Espen Olsen)
In article jamieh@uniwa.uwa.edu.au (Jamie Hamilton)
writes:
And neither do I... I have a single Concentric
on my Speed Twin. It is not the carb originally fitted, and has a strange
'choke' handle on the handlebars, connected via a cable to the top of the
carb. It operates a sort of 'piston' (or whatever you call it) inside the
carb.
Pull the cable - intake opens...
If this is the infamous 'air slide', then I never
use it. It makes the engine run rich and has in practice no effect as I
have to trickle the carb anyway...
Date: Tue, 19 Apr 94 11:06:15 BST
Amal Air Slides: Fitted as standard to all Commandos,
although may have been removed by dealers for the reasons already stated.
I spent hours with a frend kicking over a Commando,
trying to get the thing started until we realised you had to 'engage' or
'operate' the choke lever to switch the choke off. You pull the cable to
remove the choke slides from the airflow. Yes the slides must disapear
completely from the airflow to get full throttle, the same is also true
of the Throttle Slides.
I recall the starting procedure on a T120 Triumph
which involved sticking rags down the Carb Belmouths. Starting procedure
on the Commando, well my one anyway:
The chokes not necessary in very hot wether, which
is why you lucky people in the states get away without one. Please make
sure the carb top hole for the choke slide is sealed if you are running
without the choke slides, for obvious reasons. If anyone is interested,
there's a special bolt for this very purpose, and I can look up the number.
Date: Tue, 19 Apr 94 07:30:54 -0600
Espen writes:
Well I have been very unhappy with my Amals at
times but I have NEVER Trickled my carb, I have been very tempted, but
I have restrained. I do however tickle my carbs when I want to experience
the full brit bike flavor. Otherwise I use the 'choke'
Date: Tue, 19 Apr 94 09:54 EST
I've retained the air slides on my Bonnie. I can't
imagine starting without them... 1st kick, even after 4-5 weeks of sitting.
My slides don't go all the way to the top either - they stick down about
1/8" at full throttle. I never ride full throttle anyway.
Date: Tue, 19 Apr 94 10:31:52 CDT
Speaking of ticklers:
Are they still available??
The strangler levers are unnecessary here in the
"tropics" of Texas.
Date: Mon, 21 Mar 94 09:41:53 GMT
Thanks to the combined wisdom of Brit-Iron I now
know exactly what overrun Backfires are and why they happen. But a few
words on Amals and Spray Tubes.
First, what are they: If you take the top off
an Amal Carb, (lets us consider a MK 1 Amal Here), the throttle slide comes
out with the needle attached to the bottom. The needle actually goes into
the needle jet at the bottom of the carb, and there is a bronze tube surrounding
the needle jet.
This tube sticks up into the main venturi (sp?)
of the carb, into the airflow. And is what's called the spray tube.
My Norton Commando carbs were fitted with sectioned
tubes from new. A sectioned tube is a tube with one half removed where
it pokes up into the air flow, the complete half facing the air inlet.
The tube is 'top hat' in shape and is knerled (sp) at the botten end to
allow an inertferance fit into the carb body from below. It fits immediately
above where the main jet holder screws into the carb. ( A picture is worth
a thousand words).
I still believe such tubes, (non Sectioned) were
used as standard on other models of Commandos. Some time back I was suffering
with backfireing and spoke to the chap at Amal who suggested Replacing
the spray tubes supplied with the new carbs with the old sectioned ones.
No suggestion of the wrong carbs or Two stroke carbs.
Further, I wrote and spoke to John Hudson (Presedent
of the Norton Owners Club and long time worker at Nortons), on the subject
of flat spots in performance and carb settings, he told me the sectioned,
(as opposed to non sectioned tubes) were used to increase fuel flow as
they [Norton] were getting concerned about the increase in main jet sizes,
upto 260 on the later 850's.
Looking in my Haynes Carb Manual for the differences
between Four and two stroke carbs, the only thing I could find was a reference
to bleed holes in the Main Jet. Its interesting in all this, to note that
there is no mention of Spray tubes in any of the manuals, or even parts
lists.
Date: Mon, 4 Apr 94 15:25:00 EDT
Commander Norton, Just took my MK1's apart and
voila the sectioned spray tubes which you have been discoursing upon stared
me in the face.
Guess they were stock on the '74 Commando. I replaced
the needle jets and found the the previous owner had reamed them out from
.106 to full bore. No wonder the pilot air screw had little effect on idle.
I noticed that the air slides were scratched and the slide bore had circular
machining marks in a very coarse pattern.
Private Norton
5.6 Determining
Carb Settings.
Date: Fri, 1 Apr 1994 10:01:59 +0000 (GMT)
Chuck sez:
Quoting from _Triumph_Twin_Restoration_: "Amal
stamp all carburettor bodies with a number sequence that is their method
of stock control. This is the build standard and up to the late Concentrics
is unique as to the internal settings of the instrument.
Thus if *any* setting was changed the assembly
received a new part number and was stored accordingly." [paragraphs deleted]
"The effect of this system can be shown by taking as an example the type
376 Monoblocs fitted to the 5T and T100 in the years from 1955. Both are
of 15/16" bore with the same slide, needle position, and needle jet. However,
the main and pilot jets are respectively 200 and 30 or 220 and 25 so the
assemblies are numbered 376/25 and 376/35. Thus it is easy to check that
the correct item is fitted.
" "A perfectionist would seek to fit a carburettor
with the correct number stamped on it but otherwise there is no obstacle
to just changing the settings to the correct ones for the machine in question."
This is the source of the confusion I stated yesterday, where the '67 TR6R
and T120R's carbs are spec'ed to have the same jets/slide/needle yet they
have different build standard numbers. It's not a case of left/right handedness
since Triumph's twin carb heads have splayed intake ports to allow 2 normal
(float bowl on left) Monoblocs to fit. Perhaps there is an internal setting
other than those listed in the table I quoted yesterday? I dunno.
Date: Fri, 1 Apr 94 14:26 EST
>>One thing I don't understand though is that
the same table quoted above lists the
This way both float bowls will be on the outside.
I might be wrong, but I don't think monoblocs came in left and right, which
would explain why some twins had chopped float bowls. The only bike I've
got with a monobloc (greeves) has the original carb and it requires you
to stick your hand through the muffler to tickle it, they probably would
have used the other side carb if one had been available.
Concentrics came in left and right. I suspect
the /239 /95 numbers specify the exact state of tune (slide, jet, needle)
or the bike it was originally used on, specifically engineered to give
originality freaks something else to be anal about.
Date: Sat, 2 Apr 94 15:23:54 PST
Tim Keane says:
Probably specifies right and left hand carbs.
Date: Wed, 01 Dec 1993 15:01:23 +0000
When striping a carb, be very carefull to check
and note how far in EVERY adjuster screw is before you remove it.
The screws are measured by turing them in till
they stop, count in 1/4 turns at least. Such adjuster screws are: Idle
mixture and throttle stop. You may also find that the screws are adjusted
slightly differently for each carb, assuming you have a multi cylinder
and multi carb bike.
Aside from that, make sure that whereever you
do this is clean, I mean _spotless_ NOT the garage floor, try the kitchen
table, or dining table. It kinda goes without saying that all worn parts
sould be replaced but its difficult to gauge the wear on the throttle slides,
this is different for each type of carb and bike they are on.
Good time to replace all the gaskets, unless it
has rubber 'O' rings which can be re-used if they are in good condition.
If this is a CV carb, check the diaphram above the throttle slide for any
holes, and, as with the rest replace if there is any dammage.
Note: A CV carb is one where the throttle cable
is connected to levers operating a butterfly valve, rather than pulling
the throttle slide directly.
If this is a mulit carb bike then you will need
to re-balance them when they go back on the bike, with CV Carbs this is
done normally with a vacume gauge, if not CV carbs then mail me back and
i'll tell you what to do with the yaks blood.
Date: Wed, 19 Jan 94 17:25:32 -0700
Hello all Will try to bring names and numbers
tommorrow But the slow speed jet for the amals IS available from British
only. I got a set from 20 to 35 for my units. Definitly have them send
you a 109 needle jet too. I went through a summer of grief, before I finally
bought new needle jets and solved my high speed and steady throttle richness
problems. I now do these things to all of my bikes with amals:
1. New needle jets always
Above cost is total $80 ~ $90 per carb, much cheaper
than new or jap replacements.
Date: Thu, 20 Jan 1994 09:32:34 -0500 (EST)
You don't replace the seats? If the needle's worn,
won't the seats begrooved too, or doesn't that usually happen with Amals?
5.9 Determining
Throttle Slide Wear.
Date: Tue, 8 Mar 1994 13:05:53 -0800 (PST)
How do you know when the slides are worn?
My Commando 750 will not idle at a constant speed
when hot, but will slowly cycle between fast and slow. Otherwise everything
seems OK. Starts well cold, runs fine at intermediate and open throttle
settings.
Is it time to resleeve?
Date: Tue, 8 Mar 94 21:08:11 -0500 (EST)
They need sleeving when they rattle too much.
If you don't know how much too much is, pull the slides out and look at
the intake side - there's a round spot the size of the intake side of the
card where there's less wear, it's from the rattling at idle when there's
the most vacuum.
Actually you can save yourself the trouble, all
amals are shit and if the bike's got more than 10K miles on it they're
shot, and if it's got less than 10K miles on it they're probably shot too.
Send 'em to Lund, you won't regret it.
While you've got the carbs off might as well do
the regular maintenance, like checking the valves and points, then while
you've got the tank off you should patch up the wiring under the tank that
the previous owner kluged together, while you've got the wiring off the
coils might as well go to some hotter coils, as long as the bike's disabled
for a week you might as well check the rings and valve guides, it's easier
to pop the head if you pull the engine, as long as the bike's out of comission
for a couple of weeks while the guides are being replaced and seats are
being cut you might as well crack the cases and have the crank balanced,
with the engine out of the frame you can see the slop in the swingarm pivot
and the head bearings so it's time for tapered head bearings and new swingarm
bushes, while it's this far apart you might as well have the frame powdered,
and now spring rolls around and the bike's apart and there's a real nice
T120 cafe racer for a good price in the papers that only needs the carbs
adjusted.
Maybe it'd be easier to just live with an erratic
idle.
Date: Thu, 10 Mar 94 08:08:18 -0700
Someone asked how to tell if a AMal carb is worn,
well if it is the original, has not been resleeved, then it is WORN. Hey
these were not built to a high standard, Brit bikes we cherish now were
the Chevys and Fords of their industry. The whole bike was built to a price.
Unfortuneately the Brits lost track of technology
about 1946. As previously stated LUnds is the place to send the carbs,
I have had 6 carbs worked over by Lunds and they do great work.
Be certain that on Mono blocs that he machines
the outer jet block surface and the float bowl gasket surface. Install
a NEW needle JET #106 when you do this. These 2 things are the most important
improvements you can do. I always install the new jet and a viton tipped
float needle. When I do this the carbs are almost as good as mickeyunis.
Date: Thu, 10 Mar 94 12:16:12 -0700
In response to a couple of questions about Amals.
The reason I recommend that the needle jet be replaced is that it is commonly
worn and a worn one signifcantly effects mixture strength. No I tried to
look at my old ones through a microscope and could not see any 'wear' or
erosion. But replacing them with the same size fixed the rich running on
acceleration and steady running.
The standard float needles are white to yellow
and are the same material throughout. The viton tipped units are with a
steel or brass body and a viton (rubber) tip. Seals MUCH better.
Lunds bores the body to clean it up. Then MATCHES
your supplied slide by sleeving it. I do not think he uses an adhesive
to attach the slide to the sleeve. (anything and gasoline don't mix). At
$105 per pair, I don't think it makes financial sense to possibly destroy
a unobtainium body (monoblocs and GP's), one week turn around (really)
time helps too. Much cheaper than a new set or even a properly prepared
aftermarket set. Keeps it original too. This process will not allow new
slides to be installed in the body again.
5.10 Setting
up and Syncronising Twin Carbs.
Date: Mon, 14 Feb 94 10:25:34 GMT
The carbs:
Each carb is stamped with a number to denote size,
range and setup, ie 932/035 gives 900 series, 32mm and 035 Spec, there's
a table in Bacons restoration guide which gives all the setups, but as
there's no mention of Sectioned Spray Tubes, so I'm not sure how good it
is.
When balancing the carbs, and setting the cables
so they pull together, try putting your left hand under the carbs, light
side up, and feeling the throttle stop screws with your forefinger and
thumb, go on. Then by raising and lowering the slides with the throttle
control, you can feel the slides move. (All this without taking anything
off the bike.)
Date: Mon, 14 Feb 1994 14:18:35 +0800
>Peter Aslan writes:
The only problem with the above procedure is that
it although it may assure simultaneous slide movement, it doesn't address
the relative positions of the slides. One cable can be adjusted longer
or shorter but compensated for by the idle adjust screw. Mine was.
I'd like to suggest an easy way to adjust the
slides: Remove the air filter. You'll need a few inches of solid core insulated
copper wire. About the length and guage of a Q-Tip shaft. I've used toothpicks
in a pinch. Anything,as long as it's rigid and about that diameter.
Cut 2 pieces about 3 to 4 inches long. Place one
end of each wire into the carb mouth, and rest the ends under the lips
on the slides. The centers of the wires should now be resting on the flat
edge of the carb opening, with about 2 inches extending out of the carb.
The idea is that if one wire is resting at a different angle, the slides
are at a different height(out of synch). This is much more accurate than
eyeballing them.
Make sure the slide stop screws used for idle
adjustment are fully backed off, ie not touching the slides. Adjust the
cables on top of the carbs until the angle is the same. Slowly turn the
throttle control a bit. Both wires should start moving at exactly the same
moment. If not, re-adjust cables until desired effect is obtained.
Now turn the idle screws previously backed-off
until they both just touch the slides. You'll know this because the wire
will start moving at that point. After doing both carbs, give 'em about
1
1/2 turns each. This will be close to where it should be.
Since both carbs are now in synch, do any idle
adjusting equally to each carb. The whole routine is more work, but will
result in a smoother running engine.
Date: Tue, 15 Feb 94 15:14:25 GMT
From a recent dissatation on the subject.
The point was supposed to be that this would be
the final step, In other words, after the idle speed had been set on both
carbs. In addition, it allows the carb cables to be adjusted to pull from
the throttle stop screws together, without removing anything from the bike,
rather novel for a British Bike.
Another, interesting technique to set idle speeds
on both cylinders albeit rather obvious, is as a final check, remove each
spark plug in turn and the engine should run/faulter at the same rate/time.
This should be done before setting the cables as above, The idea being
that each cylinder might require a slightly different adjustment, and therefore
it is impossible to set the throttle stops on each carb the same.
Kind of the same as setting the rear wheel alignment
by measuring the turns on the adjuster nuts.
Incidentally, over the years I have seen all manor
of techniques for balancing carb cables, ranging from metal rods to ball
bearings. I guess its whatever your happy with but the duty of members
of this list to illustrate their own, imaginative solutions.
Date: Tue, 15 Feb 1994 16:18:35 +0800
I think that this is a capital idea Peter I used
to do this until I ran out of unsuspecting friends, damn it usually took
two friends per tune up (or one friend per cylinder). Until I found out
about insulated spark plug pliers, now I gots good running bikes and friends
too.
Be careful with electronic ignition bikes as many
cannot tolerate the ungrounded spark path and it can fry your system. Alternatively
you could hold the points open when testing balance or unplug that points
wire. I always finish off the balance by checking idle and off idle exhaust
pressure.
Of course I have no crossover tubes to contend
with in the exhaust system. Shoulda bought a basket case, I have better
luck with them.
Date: Mon, 21 Mar 1994 12:17:13 -0600
Could someone give me the play by play for syncronizing
the carbs on my T140D? I have a book with the basic procedure but they
don't tell you how to set the Trottle Stop Screw and Pilot Air Screw when
you FIRST BEGIN (ie before you start taking off the plug leads and adjusting).
Also, I would like to know if anyone has a book
specifically on AMAL carbs and where I could get one. Other than the nasty
flat spot and the big Frankenstien car coil I had to strap to the side
of her this weekend (because good ole' Lucas decided to give up around
Conroe, Texas)
I had a great ride this weekend (152 miles). Any
tips on getting rid of the flatspot would be appreciated. Oh yeah, if you
know a cheap place to get Lucas coils let me know because until I can find
one in the $30 range I'm gonna live with the Frankenstien look.
Date: Mon, 21 Mar 1994 11:04:39 +0000
Laurence T. Reiter writes:
I'd also appreciate it if someone could post this
information...I struggled with my Norton's carbs for a while this weekend.
I had no luck whatsoever in getting the bike to idle low enough so that
I could leave the engine running to fiddle with the adjustments. I tried
a couple of different settings, none dropped the idle, and I quickly became
too tired to start the bike...
Date: Tue, 22 Mar 94 09:47:09 GMT
As no one else has posted this information, I
thought I would have a go.
All that stuff about spray tubes appears to have
left people on the list speechless on the subject of Amals. This process
is in two parts, well, at least two.
First, enough to get the bike running, second,
(and after the engine is warm) setting the carbs up with final adjustments.
1.0 Before you start:
Prepare yourself as your own Moral code and Religion
allow. A quick belt of The Macallan Scotch works for me.
Now start the bike as normal, ticklers, choke
Etc.
We now need to get the bike running well enough
to warm the engine up. The Pilot screws can stay where they are, but adjust
the throttle stop screws to get an acceptable idle. Try pulling the plug
caps off and setting each cylinder in turn, again we are just trying to
get the thing 'running' at this point. Some argue that it is better to
disconnect the coils LT connections than the HT at the plug, whatever,
but you will need to isolate each cylinder in turn and set the idle speed
for each cylinder in turn, (to be the same).
Once They are the same, they should be adjusted
TOGETHER, by the same extent.
When you have each cylinder running at 500 RPM
each, when both are running the idle will be too fast, adjust together
to get an acceptable idle speed. My 850 Idles best at about 600 to 800
Rpm.
Go for a ride of no less than 10 Miles, and take
a screwdriver to adjust the idle speed through the throttle stop screws
as required. You may have thought you'd set it up OK in the garage, just
wait till you pull up at a junction or a pedestrian crossing and the bikes
revving its nuts off. Take it easy, 1/8th of a turn at a time, and adjust
for the fastest tickover. Blip the throttle from time to time as this will
settle the carb down again, (and its exactly what happens on the road).
Do this for both cylinders, and keep adjusting the throttle stop screws
to achieve 500Rpm on each.
Now run the bike on both cylinders, and by adjusting
both throttle stop screws together by exactly the same amount, set the
idle speed. When you think you've got it right, try pulling each plug cap
off and the surviving cylinder should pull/labour/die in exactly the same
way.
All this time the throttle cables have been loose,
and now need to be sorted out. The only proper way to do this is to remove
the air filter and gaters from the carbs to allow unrestricted access.
Once done put a finger on each slide and pull on the twistgrip, adjust
the cable adjusters on the carb tops until both are pulling together. When
you have done this, take up the majority of the slack in the cable from
the twistgrip, then fully open the throttles and make sure that when fully
open the carb slides disappear COMPLETELY into the carb tops, making sure
full throttle is exactly that.
Now play with the throttle, fully open, fully
closed, even let the slides drop on the springs a couple of times before
the final check that they are both rising together.
Replace the Air filter and all that stuff and
go and have a rest, to calm your nerves, you've earnt it.
In my experience, some tinkering is still necessary.
There's a hole in my jacket from carrying the screwdriver. For me its all
about going for long rides and making the final adjustments to the idle
speed. In Addition, and with respect to Brit bikes that only see the light
of day on sunny afternoons, air pressure and moisture content will effect
the carbs slightly, so be careful not to be too picky. If you are running an electronic ignition such
as Boyer, Rita, etc., it's recommended to isolate cylinders by grounding
the spark plug, not by removing the plug wire, according to Norton Tech
Digest #2. Some of those electrons, already mad about the positive ground
humiliation, take out their frustration on the elctronic ignition.
Regarding spray tubes for Amal MkI: they are shown
as part no. 928/107 for Group 11 in the 850 Commando Parts List. No mention
of sectioned tubes, though.
5.11 Setting
Concentric Float Height.
Date: Fri, 11 Mar 94 10:01:35 EST
Grit your teeth, Amal cognoscenti, while I dredge
forth a hitherto unknown (to me) addendum to the Dead Sea Scrolls i.e.
Triumph (USA) Service Bulletin Number: (General) 2/73;
"Checking and Adjusting the Amal Concentric Float
Level Occasionally you may encounter a machine which runs erratically due
to an over-rich condition. You may also find that this problem machine
is fitted with the proper size jets and has the same adjustments as a model
which runs perfectly.
After many hours of investigation, we found that
the normal cause for the problem outlined above is a high float level setting.
Check Float Level Remove the float assembly from the carburetor. Drain
gas from float bowl. Using a small screwdriver or other suitable tool,
depress the float tab which operates the float needle, until needle contacts
seat.
While holding the float in this position, measure
the distance from the top of float bowl to the top of float.
The proper measurement is .080 [Norton 1/32-1/16].
If the measurement is less than this the float
level will need lowering. SEE FIGURE 1.
[Shows distance between top of float and top of
float bowl] PUSH ON TAB ONLY- NOT ON NEEDLE Adjusting the float level:
Remove all fittings from the float bowl. Using a propane torch, heat the
bowl slightly. This will free the brass seat so it can easily be moved.
Using an 1/8 diameter rod, gently tap the brass
seat until the proper setting is attained. See Fig.2. [ Shows the float
bowl inverted and the rod pushing the seat down] CAUTION: DO NOT ATTEMPT
TO MOVE SEAT WITHOUT HEATING BOWL
By the way I saw an identical caution sign in
an outhouse in Bemidji, Minnesota last winter. This bulletin was provided
by Phil Radford, Fair Spares America, Inc. San Jose, CA. Purveyor of Parts
for the Unapproachable Norton
Date: Tue, 5 Jul 94 10:36:17 EDT
Phil Radford of Fair Spares, San Jose provided
this bulletin. He said that he puts his thumbs on the ends of the hinge
pin and then inverts the bowl to check the distance. This way it is easier
to see when the needle is about to contact the seat. Helps to have an extra
hand or two!
Date: Wed, 06 Jul 94 00:44:13 EDT
>Using a small screwdriver or other suitable tool,
depress the float tab which operates
* * * * I can speak from experience on this subject,
having spent half a season trying to get the damn float levels right on
my bike: the Amal brochure quoted above is [unintentionally] misleading,
and you may get disastrous results doing it the way they say. Phil Radford's
method, however, is just fine.
The difference is that nowadays [though not when
Amal wrote those instructions] the PIVOTS in the typical Concentric float
are significantly WORN. If you push down on the float tab to measure the
float height, the play in the pivots does not get taken up, and when the
float is later raised by the gasoline, that play can leave it as much as
1/16" higher than your adjustments intended.
To compensate for this play, raise the float with
your finger until the needle hits the seat, or [as Phil does it] turn the
bowl upside down and let gravity do it. The problem with raising the float
instead of pushing down the tab [or with turning it upside-down] is that
the hinge pin doesn't stay in its groove. Some authorities suggest peening
the groove in the bowl to keep the pin in place. I epoxied it instead,
which seemed a bit more undo-able if I need to undo it someday.
Getting the float level right without holding
the pin down somehow is very difficult, and the pin may keep on moving
around while the carb is in use, thwarting your adjustment. (By the way,
the INOA Tech Digest recommends 3/32" for a Norton, which is what I used.
I don't see why this would change by brand of bike). All in all, a little
on the low side is probably better than too high, and the different specs
might exist because some incorporate "safety factors." If the float is
a little low, the tickler will not operate as quickly (or perhaps at all),
and the bowl might possibly "run out of gas" under extreme throttle conditions.
If the level is too high, however, you get extreme richness with no apparent
cause, and vibration can even make gasoline splash out of the tickler-holes
at idle. If the float level height is within these limits, however, I don't
see how some variation would significantly affect the mixture.
P.S. I've noticed that most people, at least around
here, pronounce Amal with the accent on the first syllable: "A-mul". However,
since the word was derived from "Amalgamated [Carburettors]," shouldn't
it be pronounced "uh-MAL"? Does anybody know the history of this?
Date: Tue, 12 Jul 94 11:21:28 EDT
Regarding the correct float level for Amal concentric
carbs for Norton Commandos: The Norton Tech Digest says to have the float
top 3/32 inch *ABOVE* the float bowl top.
According to the Triumph service bulletin and
Phil Radford of Fair Spares (USA) this is WRONG. THe float top should be
*BELOW* the top of the float bowl casting [Minimum 0.080 inch for Triumphs
and 1/32 -1/16 inch for Commandos]
When asked about the error in the Tech Digest,
Phil said "Remember, it was written by laymen".
5.12 Re-Jetting
for Modern Fuels.
Date: Thu, 10 Mar 94 10:46:45 CST
When I brought my '68 Lightning out of retirement
it was running very rich, especially on the highway. This was with relatively
unworn, standard jetting and the bike had been running properly before
"storage". I checked also for things like a leaky float and needle or plugged
air cleaner.
Steve at Austin Cycle Salvage (the brit parts
guys around here) said that that was very common on bikes that had run
on the "old gas" and that the "new gas" flow rates were different enough
to require rejetting.
We went leaner on the main and needle jets and
it fixed the problem.
Date: Fri, 21 Jan 1994 17:00:47 -0800 (PST)
Oh, boy !, a couple of weeks ago, I cudn't even
spell Internet, and now I are one! Hot damn! I don't know if you're supposed
to write a FAQ just cause you feel like it or not, but I've seen a couple
of frequently asked questions now, and I think I can help, so here goes:
First, what I read in a book about Amal (or for
all that matter, slide type carbs in general) many years ago. Some Brit
outfit used to put out a series of books, like, _Book of the Royal Enfield_,
_Book of the AJS_, the Villiers Engine, the BSA, etc, ad nauseam. They
were published in the fifties, but in the umpteenth editions -the first
printings were all pre-war. These books were REAL interesting, and cheap
like borscht. It seems to me they were about a buck and a half at British
Motorcycles on Fraser Street in Vancouver in the mid fifties. Every time
I got ahold of another old wreck of a bike for 50 bucks or so, like my
first Frantic Banana, for instance, I would run off to British, and see
if they had one that covered my latest "new" bike. They usually did, but
unfortunately, they tried to cover all models ever made, so when I got
a scarily current '52 AJ 500, for instance, the trusty old _Book of the
AJS_ was available, but spent more time telling me how to set the timing
in the '28 1000cc Vee Twin (Yes, Easy Riders, Everybody made one at one
time or another) than how to fix my 2nd gear jump-out. Still, they had
enough in there to get a guy out of most jams, and these were long before
the days when you could go out and buy a Haynes Manual.
The other alternative was to order a genuine factory
workshop manual, which cost about as much as most of the motorcycles my
friends and I were running. (or pushing) But they made great reading. I
particularly remember one time, when all the sparks seemed to be used up
in a magneto on one of my old treasures (any of which I'd probly trade
a finger for today), the book of the whatever (RE that time, I think) confidently
advised me that I would find nothing of interest to the casual user inside,
and that the only thing to do was to put it on the 3:15 Wednesday Train
to Ipswitch-On-Clyde or some suitably yorkshire-pudding kind of place,
and satisfaction would be mine within the week! They even had a damn train
schedule in the book! Honest! I guess it never occurred to them that some
of their fine hand-built sand-cast models might some day make it out to
the colonies! But then, that's what was great about britbikes (or anything)
-they made them for themselves, and thus expected to have to face irate
consumers if they turned out to dive into corners like a Virago, or etc.
If some colonials wanted to order one up, too, well wouldn't that be a
surprise!
Anyway, (slap!), to get back on track a tad here,
one thing all these books of the * had in common was a rundown on tuning
the Amal Standard Carburetter. (I always thought that was a damn strange
way to spell carburetor 'til I saw a brit movie one day, and I'm blowed
if that isn't the way the guy said it - "Trouble with the car burr it er,
I should think." Well I could get behind gearbox by then, (as it had not
yet been precluded by those of us needing a term less anti-pejorative than
the lame pussyass nomenclature of "gay," which at the time still meant
having snuck a little too much party fuel at Christmas), and I even let
the odd 'gudgeon pin' slip, but carr burr it er was always just too much.
Oh yeh! (Slap!) So the Amal standard carb, precursor
to the monobloc, looked a lot like an old TT, only tackier. It had a tubular
main body, and a separate float bowl, so that all angles of induction tract
and carb placement could be accomodated. It had a slide up the center,
a needle in the slide, and a jet block at the bottom, with the needle jet
at the top of it, and the main jet feeding it from the very bottom. For
"Idling," (I never did think motorcycles were supposed to "idle" -got into
a yelling match one day with some squid at a friend's motorcycle repair
shop who was freaking because the "idle" speed was fluctuating and causing
stalls at lights on his zinger. Idle -God, in between cruises on his Harley,
gave you fingers separate from your wrist so you can diddle the front brake
and still keep the motor running, you reptile! Get a life! Wouldn't You
Rather Drive a Buick?) And, this little book of the *, which fit into your
back jeans pocket, but had a TON of good info in between the dreck about
the 3:15 to Ipswitch, and the '32 Veetwin.
Such as the compleat rundowne on tuning the Amal
carburriter, or however you spell that crittur. It had a little picture
of each of The Ranges. Such as closed to 1/8 throttle, 1/8 to 1/4, 1/4
to 3/4, and 3/4 to full. It explained that the fuel is supplied to the
airstream in different ways for each range. It told me that the main range
I ride in is 1/4 to 3/4, and that this range is fed by the needle jet.
And that to lean the mixture in this range, I need to drop the needle,
relative to the slide. To richen, I need to pull the needle up. I don't
think it told me how to do this, exactly, people still expected other people
to have a brain in those days, -but that was enough. It also told me that
the onliest way to vary the mix in the top end of the range -3/4 to wfo
-was to change the main jet, that little thing with the hole in it at the
bottom of the jet block. It stood to reason that, providing it was big
enough, it couldn't make much difference to mid range running, because
the needle jet restricted the flow in that range. And I can't remember
if it told me, or I figured out for myself, that I wouldn't need to be
finding different mainjets for fine tuning if I wasn't running around above
3/4 throttle.
It also told me that from closed to 1/8 - they
called it "low-speed running -they didn't mention "idle" -why get a kid's
hopes up? -Real Motorcycles don't "idle" -was controlled by the pilot screw.
That was the little screw on the side of the carb. Obviously a little needle
valve. Whether it let in air or fuel, I never did figure out - damn thing
never had much effect anyway. But the drill was to set as close to idle
(I remember! -it was "tick-over! Yeh bang blap pop pop tick. Sure.) as
you could get it, then screw with the screw to make it run faster, then
adjust the throttle stop downward, and do it again until it "ticked over"
best. From 1/8 to 1/4, so they said, was controlled by the cutaway angle
on the back of the throttle slide. This cutaway also controlled the mixture
during the transition onto the needle jet.
Since the factory pretty well chose the slide
that was in there, I always assumed that the one I had was just about right,
and the faith never faltered until I bought that damn Goldstar, which had
a 1 1/2 GP carb that didn't seem to know what transition was A-tall. Full
On or Full Off was that sucker's favourite two settings, and the price
of throttle slides being about a month's scrounging for this kid at the
time, I never did get a chance to find out if changing cutaways would really
make a difference. Anyway, the needle is the one we need the most, and
by some strange coincidence, it's the one you don't need extra parts to
tune. At least, not if it's ballpark to begin with. How to find out if
your mixture is lean or rich? Do a "sparking-plug check," the little book
said. To do this, run the bike for awhile in the range you're checking,
starting of course with mid-range. As in, pull up a mild hill in 3rd or
4th gear at half throttle, in reasonable rpm range, and after 30 sec. or
so, quickly and simultaneously pull in clutch, stop motor, pull off to
side of road, whip bike up on stand or against tree as the case may be,
and whip out the plug. (You DO have your plug wrench in your back pocket
at this point, don't you?)
Have a look at the porcelain insulator tip inside
the plug. Not that one, dummy! If it says, "Champion," you've got it upside
down. The tip should be chocolate brown. If it's black, you're too rich
and if it's white, you're too lean. Remember, this is just for the needle
position. If you can't get it lean enough by dropping the needle to the
bottom, it's time to get another needle and or jet. They DO wear, after
all. Ditto but backwards for too lean.
Once this is done, it's time to check out full
bore. Find a hill (if you're a speed freak, 0 degrees is fine) where you
can run at a constant full throttle for 30 sec or so, and do it again,
but wfo. If your tip's black, (ooh, nasty thought, that one! get thee hence,
nasty thought!) you need to drop your jetsize. That's the mainjet, in the
bottom of the jetblock. If it's white, you have two choices: stay below
3/4 throttle, or pop in a bigger mainjet. There is a slight interrelationship
between main and needle jets, but not much. Obviously, for instance, if
your mainjet is Really small, it won't pass enough fuel to the needle jet,
so if you can't get a rich enough needle setting at the top (clip at bottom
of the needle, don't forget), then it may be the fault of a too-small mainjet.
But equally obviously, a smaller mainjet will not satisfactorily cure the
too-rich needle blues -not without being a real starvation case when you
get to wfo range. Although this wisdom originally came to me from drawings
and prose penned about Amal Standard carbs in the early '30's, it has worked
for me ever since, on Monos, Concentrics, TT's, GP's, Mikunis, - the principle
is even the same (sort of) for SU's on all manner of strange leaky automobiles.
Just think about how it works, and you'll probly
be able to figure out how to fix it. This of course assumes the conscientious
owner will have first made sure that the fuel level in the float bowl is
right. If it's pissing gas as soon as you turn the tap on, don't be wasting
too much time switching main jets! If you can't tickle up a good drip outta
there, it may be time to check that primary fuel flow -white spider nests
in the float needle valve seat just don't cut it, not even on the ol' sledgehammer
engineered greats from Over There.
5.14 The
Commando Backfire Bomber.
Date: Tue, 15 Mar 94 09:12:02 GMT
About three years ago, as part of the continuing
process of restoring the old Norton to good as new condition, I decided
to replace the carbs, (14K miles on the old ones, and an iratic idle) and
the points with a Boyer unit.
Its worth pointing out now that I have a profesional
qualification in Electrical Engineering. So, using the theory that 'it
was the last thing you touched that broke it', and 'its never a good idear
to change to much at the same time', I first replaced the Points and advance
mecanisim with the boyer unit. After several test rides, getting the thing
set up and enjoying the thought of never having to strobe the thing ever
again, I then replaced the carbs.
A Note for any one who is considering ordering
new carbs: Strip the old ones and make a note of the following: Throttle
Valve Size, Needle jet and Main jet size, and the size of the needle itself,
(the number of ident rings, not the clip rings at the top of the needle).
And specify the same when ordering the replacements. On go the new carbs,
I checked and replaced the needle and Main Jets to conform to the old ones.
The bike started first time, to my supprise, and
I was now running with new carbs and Electronic Ignition. Surely the bike
will run perfectly now.
Well, over the weeks that followed, I became increasingly
aware of the Engine backfireing on overrun, and the fact the thing vibrated
lower down and where I was spending most of my time riding.
I then decided to investigate the Ignition side
of things, and replaced the Boyer unit with the old points and stuff, Still
no difference, I was able to get the bike backfiring on overrun by just
bliping the throttle. Checking the points I noticed that the metal spring
of the points, these were new ones, were hitting one of the adjusting screws.
Comparing with the old ones, the new points had a more prenounced 'D' shape
to them, the spring was rounder at the back of the points. So I filed,
cleaned and replaced the old points. *Still Backfiring*
The next candidate for suspicion were the points
capacitors, after all, this is exactly what the capacitors are supposed
to stop. Mounted on the coil bracket the, two round capacitors are bolted
to a plate at one end and covered with a rubber cover. They have to be
replaced individually, but it wasn't a problem. *Still Backfiring*
Next candidate was the wiring itself, Power comes
from the ignition switch, through a Brown/Blue wire, through the Balast
Resistor to both coils, the other side of the coils connect to the wires
to the points with the capacitors connected across the points. Hmmmmm,
maybe a bad earth. The coil bracket had been powder coated, so had the
engine stedy at the top of the engine, maybe there was no good earth, (this
is a common problem on rebuilt bikes and cars). So I ran a wire from the
harness earth under the tank, to one of the three socket screws fixing
the top engine steady, although there was a tantalising moment where I
realy though I'd fixed it, no, *Still Backfiring*
A long night follwed where I rigged up a completely
seperate ignition harness connected to a completely seperate battery, still
no good. Then, stairing at the wiring diagram the penny dropped, the coils
were wired back to front. Remember that qualification I mentioned earlier,
this is a POSITIVE Earth bike, the terminal of the coils that run to the
points should be the POSITIVE terminal.
I was trying to figure if I had damaged the coils
connecting them the wrong way round, and rememberd that the bike had appeared
fine at first then started backfiring, maybe the internal insulation of
the coils had been breaking down. One new set of coils later, (Now made
in Germany, not Lucas) and THE BIKE WAS STILL BACKFIREING.
Back to the wiring, there was still a wire unaccounted
for, the balast resistor feeds the NEGATIVE terminal on both coils, but
two wires went to each NEGATIVE terminal. Power in and out of one coil,
power in the other so where does this wire go ? I never found out. I concluded
that as all the electrics checked out, the problem MUST lie elsewhere.
We now turn our attention to the Carbs. I stripped
both the new and old carbs and looked for differences, sure enough, the
Old carb had a sectioned spray tube. (This is the bronze tube fixed to
the base of the carb body the need
From: John Pinkham
From: Chuck Stringer
> Do they require a different air filter(s)?
I've seen a single Mk2
> replace dual Mk1's, would dual Mk2's be overkill?
> Is the conversion worth the effort?
From: Pete Serrino
>So what's the difference between the MKl and
MKll, or for that matter
>the MKl 1/2? Also, I saw an article on replacing
the tickler with a
>larger button for easier use. It looks pretty
good. Has anyone tried
>the conversion?
>John Pinkham writes:
>>Do they require a different air filter(s)?
I've seen a single Mk2
>> replace dual Mk1's, would dual Mk2's be overkill?
>> Is the conversion worth the effort?
>>
>Chuck Writes:
>So what's the difference between the MKl and
MKll, or for that matter
>the MKl 1/2? Also, I saw an article on replacing
the tickler with a
>larger button for easier use. It looks pretty
good. Has anyone tried
>the conversion?
MK1 = Two bolt flange connection, tickler and
air slide
MK2 = Round connector, fuel enricher type choke
on lever or cable, no air slide
MK1 1/2 = Mk1 flange with Mk2 features.
From: Your Name Here
From: alastair@cadence.com (Alastair Young)
At 12:38 PM 4/19/94 -0600,
>Whatta bunch of wimps. Hell I kin remember back
in '01 when we did'nt
>have the fancy carbs you young whippersnappers
are whinning about.
>
>Try a real mans carb, a surface carb. This one
coaxes a airstream over
>a pool of gas in the hope that enough gas would
evaporate into the
>stream and eventually flow through the 'atmospheric'
inlet valve and
>maybe the vibrator controlled ignition would
ignite the maybe rich or
>lean enough fuel air mixture.
From: kichline@mpd.tandem.com (Chuck Kichline)
From: clem@romulus.cray.com (Terry Drehmel
{x68282 CF/ENG})
>When I look at very old motorcycles, it is amazing
that they were considered
>much better methods of transportation that horse
and buggy. Each year they
>just get better.
From: alastair@cadence.com (Alastair Young)
At 2:20 PM 4/19/94 -0500,
>> PS Surface carb, heck we just dribbled gas
from a hose into the intake!!
>>
>I've seen a Wal Phillips "fuel injector" that
came with a pile of Enfield
>bits that was just that (as far as I could tell).
The linkage twiddled two
>butterflys that were set with a differential
between them. The fuel hose
>went in the top, with some form of flow control
(a rotating V slot?) working
>off a third bell crank between them.
>
>There were adds for it in CYCLE in the late
60's, and I've held one in my
>hand. Anybody have any more on these?
From: Roy Armstrong
>Do the Mk2s require different rubber connectors
to the air filter front
>plate? Do they require a different air filter(s)?
I've seen a single Mk2
>replace dual Mk1's, would dual Mk2's be overkill?
>Is the conversion worth the effort?
From: Jamie Hamilton
From: John Kula
From: bman1@aol.com
From: unisql!brg@cs.utexas.edu (Bruce Graham)
>Anyway I'll get to the point: I'm somewhat
>interested in trying to put my Commando motor
into a Featherbed frame. I was
>never really able to get that slightly 'wandering'
feeling to totally go away
>Very interesting point about the Commando (and
something I continually forget)
>-- those isolastics. Now, a Commando engine
bolted into a featherbed frame
>might be interesting (if only Mick Hemmings
would tell me the balance factor
>he uses :-) ).
From: Chuck Stringer
> Anyway I'll get to the point: I'm somewhat
> interested in trying to put my Commando motor
into a Featherbed
> frame. I was never really able to get that
slightly 'wandering'
> feeling to totally go away
From: paslan@uk.mdis.com (Peter Azlan)
Engine/Frame number 31(something).
Amal Mk1 Concentric 32mm carbs stamped 932/35.
Mains: 260.
Throttle Slide: No 3 1/2.
Needle Position: 2 (mid).
Nedle Jet: 106, (with a small hole through it
half way up).
Needle: 4 ring, (Not sure of the part number).
Spray Tube: Cutaway at the back, (again, unsure
of Part No).
From: Nancy J Caputo
'73 850 Interstate
Boyer 750 exhaust pipes (no balance tube)
resleeved concentrics, 5K on them
4 ring needle, clip in middle 260 main
.105 needle jet <----
N7Y
sectioned spray tubes
Contis <----
From: Peter Azlan
From: Jamie Hamilton
Non standard short exhaust pipes no baffles,
no balance tube.
Amal Mk IIs Dont know jet size - no complaints
From: Eric Rogge
1973 850 Commando Roadster
750 pipes, no cross-over
750/850 air filter
Resleeved carbs with 3k miles (don't know much
else about their config)
Boyer ignition TT-100 tires (tyres?)
Dunstall setbacks (much more comfortable)
Low bars Koni's More stainless steel than Jaws.
Runs great, hot idles like s***.
From: Nancy J Caputo
From: paslan@uk.mdis.com (Peter Azlan)
From: Bob Cram
From: Your Name Here
>Since then I have been having misfire problems
from about one-quarter to one-half
>throttle, usually in the 2500 to 3500 rpm range,
and it tends to be worse while
>accelerating. Plug readings show the bike is
running rich. I have rebuilt MANY anal carbs.
From: Stephen Hill 356-9389
>Does anyone have any idea what the proper main
jet size is? Do you think this could
>be the cause of the overly rich mixture and
misfire problems I'm having? Personally,
>I'm dubious that main jet size (especially such
a small difference as 180 to 190) would
>affect mixture and misfire problems in the one-quarter
to one-half throttle range,
>where the mixture is governed by the needle
and not the main jet. However, since
>the needle seats into the jet, and a smaller
jet size would mean less gas flow,
>maybe???? Anybody out there got any brilliant
advice on this?"
From: Chuck Kichline
From: Chuck Kichline
>
> Regarding the gasoline question, I remember
reading in Vintage Bike that all
> Triumphs should run on at least 93 octane (even
though my workshop manual
> specifies 91 as the minimum), which can be
a bit hard to find these days, at
> least in Canada. I buy the highest I can find
easily here, which is 92 octane,
> and put in a tablespoon of octane booster with
each tank fill.
From: mason@ftp.com (Latte' Jed)
> 2 or 3 points)? I understood that it was the
testing method (something
> about Research Octane Number) that changed
and not the actual fuel.
> If so, we shouldn't need the unobtanium fuel.
> Gotta be a Petroleum Engineer out there somewhere!
>
>
> > Regarding the gasoline question, I remember
reading in Vintage Bike
> > that all Triumphs should run on at least
93 octane (even though my
> > workshop manual specifies 91 as the minimum),
which can be a bit hard
> > to find these days, at least in Canada. I
buy the highest I can find
> > easily here, which is 92 octane, and put
in a tablespoon of octane
> > booster with each tank fill.
From: Pete Serrino
>After much frustration, Steve Tuffs steered
me into needle jets and
>needles a step leaner than stock and the "new
style" (whatever that was).
From: Ralph Merwin
>Main Jet question
> With all the discussion of jetting problems
with the Amals - is there ever a
> cure? Getting a good tickover with the Norton
seems next to impossible.
> Slides are not visibly worn, carbs totally
cleaned and all passages blown
> out. New: air cleaner, plugs, Boyer, wires.
>
> All my other bikes I was able to get to sit
there and idle forever.
> Two-strokes, four strokes, singles, twins.
Even race-type bikes running big
> Mikunis ( Three 34mm's on an 850 triple)
>
> So, is it the Amals?
From: John Knobel
Getting a good tickover with the Norton seems
next to impossible. Slides are not visibly worn, carbs totally cleaned
and all passages blown out. New: air cleaner, plugs, Boyer, wires. All
my other bikes I was able to get to sit there and idle forever. Two-strokes,
four strokes, singles, twins. Even race-type bikes running big Mikunis
( Three 34mm's on an 850 triple) So, is it the Amals?
Mk 1.5's? It's nothing I can't live with , but
just thought I'd enquire. - John
From: mason@ftp.com (Latte' Jed)
> a AMal carb is worn, well if it is the original,
has not been resleeved,
> then it is WORN."
From: Bob Cram
From: Rolf Clausen
> My original question about whether switching
my 72 Bonnie from 190 to 180 main
> jets would solve my misfire problem has sparked
a lot of discussion. Anyway, I
> thought you'd like to know that I made the
switch on the weekend and
> experienced a very noticeable improvement.
The mixture is leaner now and
> plug readings are better. However, it still
misfires a bit, but over a
> narrower throttle range and not as badly.
>
> Although the books say main jets aren't supposed
to have an influence until
> three-quarter throttle, it obviously made a
difference in my case in the
> one-eighth to one-half throttle range. I presume
that this is because all fuel
> goes through the main jet to get to the needle
jet. Thus the quantity of fuel
> flow is directly affected by main jet size
even at lower throttle openings.
> What the books should say is that the main
jet size is the sole influence on
> fuel flow above three-quarter throttle, and
below that it is a factor along
> with throttle cutaway, needle jet size, needle
size, etc. Does that make
> sense? Ahem, may I express my h.o.? Thank you..
From: Bob Cram
>The fuel will be restricted and hence metered
by the part of the carb that provides the
>biggest resistance. As the main jet can deliver
enough fuel for full throttle riding, it
>will not restrict fuel very much at smaller
throttle openings. . . .
>Reducing main jet size should lead to other
problems at higher speeds, lean and hot
>running.
From: Rolf Clausen
>One piece of information in my original message
about this is that different Triumph
>factory sources gave different specs for this
year for the Bonneville. Some said 190
>for the main jet; some said some 180; some listed
both.
From: Bob Cram
From: Bob Cram
From: Rob Brotherston
>this is in a chapter on "Servicing Common Components--British
Models" in the
>seventh edition (1974) of "Modern Motorcyle
Mechanics" by J.B. Nicholson. The
>Nicholson brothers ran a mainly British motorcycle
shop in Saskatoon, Canada from
>the mid-30s to mid-70s, and their book was the
standard textbook in Canada for
>motorcycle mechanics in Canada in that period.
From: Steve Bacon
From: rdb@strata.com (Robert D. Burget)
From: Your Name Here
From: Cindy Grant
>The local triumph expert says they were all
removed because the operation wasn't
>intuitive (turn the lever cw to open the slides
and ccw to 'close' them) and the cables
>would break and allow the slides to drop and
cause very rich running. Also not real
>good on very cold mornings.
>for her. Is it running yet Cindy?????
From: alastair@cadence.com (Alastair Young)
>Does anyone actually use the air slides in their
amal carbs? I just installed some in a
>effort to be more original, and I can't seem
to get them to go all the way up, so that
>no part is visible with the throttle wide open.
I wonder if this is normal, because I've
>never stared down the carb throats of a bike
that had them installed before. Just
>wondering,
From: jamieh@uniwa.uwa.edu.au (Jamie Hamilton)
From: Roy Armstrong
>Does anyone actually use the air slides in their
amal carbs? I just installed some in a
>effort to be more original, and I can't seem
to get them to go all the way up, so that
>no part is visible with the throttle wide open.
I wonder if this is normal, because I've
>never stared down the carb throats of a bike
that had them installed before. Just
>wondering,
From: DDODGE
>"rich mixture" choke effect by excess tickling
(though this is a fire hazard) and do
>away with that extra control cable.
2) The intake pipe is quite long.
Date: Tue, 19 Apr 1994 09:39:40
>I am sorry but I am not sure what air slides
are. I have a pair of MkII
>Amals and don't know what terms like 'tickling
the carbies'. When I start I
>just move the choke lever and the handle bars
to half and open the taps
>after its fired up.
From: Peter Azlan
Starts first or second kick, wont work unless choke
is used. Always fires at first on one cylinder, then on both, (probably
the petrol flow or carbs) The choke can be taken off after about 30 Seconds.
From: Your Name Here
It makes the engine run rich and has in practice
no effect as I have to trickle the carb anyway...
From: PMGL0928
From: kichline@mpd.tandem.com (Chuck Kichline)
There used to be ticklers available for concentrics
- I think they were Spanish Amal - which made a great retro fit. They came
with a large (and tall) tickler button which overlapped the carb entry
bushing. You could tickle'em until they wept and didn't end up sniffing
your fingers later.
From: Peter Azlan
From: John Pinkham
From: tim@eskimo.com (Tim Keane)
>On the Spitfire/Lightnings the right hand and
left hand carbs are 389 and 689. What
>does the second number in the model stand for?
The difference between the
>Thunderbolt (single carb) and Lightning (dual)
Amals is in the second number, that's
>why I was hoping I could modify one of mine
to work alone.
From: mason@ftp.com (Latte' Jed)
>>TR6R carb type as 389/239 and the Bonnie carbs
as 389/95. Why would the build
>>number be different if the slide, needle, and
jets are all the same?
>
>I'm not sure but it is probably that one of
the carbs is right-handed and the other is
>left handed.
From: dwhite@atl.com (David White)
>One thing I don't understand though is that
the same table quoted above lists the
>TR6R carb type as 389/239 and the Bonnie carbs
as 389/95. Why would the build
>number be different if the slide, needle, and
jets are all the same?
From: Peter Aslan.
From: Andrew Wolf
2. New gasket set
3. Viton tipped float needles
4. Only if the above doesn't cut it, send to
Lunds to rebore the carb and sleeve the slide.
Damn good work, 1 week turnaround and SMOOOOOTH
carbs.
From: Chuck
From: Steve Moseley
From: Latte' Jed
From: Your Name Here
From: Your Name Here
From: Peter Aslan
My bike was fitted with sectioned spray tubes,
the bronze bit the needle goes into in the body of the carb. This mod was
intened to increase fuel flow without going to a bigger main jet, it was
already a 190.
From: Daniel M. Milhone
>When balancing the carbs, and setting the cables
so they pull together, try putting
>your left hand under the carbs, light side up,
and feeling the throttle stop screws with
>your forefinger and thumb, go on. Then by raising
and lowering the slides with the
>throttle control, you can feel the slides move.
(All this without taking anything off the
>bike.)
From: Peter Aslan
>When balancing the carbs, and setting the cables
so they pull together, try putting
>your left hand under the carbs, light side up,
and feeling the throttle stop screws with
>your forefinger and thumb, go on. Then by raising
and lowering the slides with the
>throttle control, you can feel the slides move.
(All this without taking anything off
>the bike.)
From: Andrew Wolf
From: lr035778@mbcr.bcm.tmc.edu (Laurence
T. Reiter)
From: Cindy Grant
>Could someone give me the play by play for syncronizing
the carbs on my T140D? I
>have a book with the basic procedure but they
don't tell you how to set the Trottle
>Stop Screw and Pilot Air Screw when you FIRST
BEGIN (ie before you start taking
>off the plug leads and adjusting).
From: Peter Aslan You can't set twin carbs up on a cold
engine, I have wasted hours and hours doing so. Also, ensure the timing
is correct, otherwise you will never get it right. Obviously you wont be
able to strobe the engine, but if it has a points Setup, check them staticaly,
remembering to lock the auto advance fully advanced (against the pull of
the springs) with the service tool washer or suitable washer/s. Make sure
the throttle slides are not hanging on the cables, there should be plenty
of slack in the handgrip and carb cables. Check for slack by pulling the
cables out of the tops of the carbs.
2.0 Setting the carbs up
from scratch:
Ensure the carbs are set to the original
manufacturers specifications. This info should be in the riders handbook,
or a good manual. Make sure you are running with the correct Jets and needles,
also spray tubes, (but we wont go into that here). Also check the little
rubber washers on the throttle and pilot screws, and the throttle slides
for ware and check for leaks in the inlet manifold. Assuming they are Mk1
Amals, screw the Pilot screws, (the horizontal ones) fully in then one
and a half turns out. (this probably holds true for other carbs. Screw
the throttle stop screws in till the heads of the screws are flush with
the top of the hole they are going into.
3.0 Final Adjustments:
With the engine still hot. Once again,
we need to isolate each cylinder in turn and set it up. Pull the HT or
LT lead from/to the coil and work on the other. Set each cylinder in turn
to run at about 500 Rpm, then start adjusting the pilot mixture through
the pilot screw.
Date: Tue, 22 Mar 94 11:54:44 EST
From: John Pinkham
From: John Pinkham
Subject: Adjusting Float Level,
Date 7/18/73
From: John Pinkham
From: MikeTnyc@aol.com
>the float needle, until the needle contacts
seat. While holding the float in this
>position, measure the distance from the top
of the float bowl to the top of float.
>The proper measurement is .080 [Norton: 1/32-1/16]
>Phil Radford of Fair Spares . . . said that
he puts his thumbs on the ends of the hinge
>pin and then inverts the bowl to check the distance.
From: John Pinkham
From: Chuck Kichline
From: Peter Snidal
From: Peter Azlan