Date: Tue, 16 Jun 1998 07:19:17 -0700
From: Tom Davenport
Certainly Art X has a point re: replace stock unit with Boyer,, BUT: Sonny Routt isn't the only one who used the heavy duty springs on AAU's as that was a well known manoeuvre in the 70's for curing idles that wouldn't drop down to the same RPM consistently.
In fact, I was so impressed by it that I have a Lucas parts envelope from some of those sitting in my toolbox at home (can post the Part Number on Saturday unless Phil Pick or someone has it more handy) as a ready reference, even though I personally do not ride a bike needing that mod.
By and large I have no complaint about the AAU used on the 73 and later bikes; don't recall what the date of introduction of "late type" AAU was on those. Earlier had problems with point cam getting loose on shaft and consequential wandering timing. Don't know if that was from poor materials choice or poor manufacturing tolerance or a combination. The latest ones didn't seem to loosen up as much. Even the earlier were pretty good when maintained with a bit of grease on the pivots and shaft. Like the (in)famous Zener Diode, possibly another of Jose Lucas' overly maligned parts where more often than not the problem arose from the nut that holds on the throttle.
Tom Davenport
Date: Tue, 16 Jun 1998 09:52:58 -0700
From: John Mead
> On Tue 16 Jun, Tom Davenport wrote:
> > Certainly Art X has a point re: replace stock unit with Boyer,,
BUT: Sonny
> > Routt isn't the only one who used the heavy duty springs on AAU's
as that
> > was a well known manoeuvre in the 70's for curing idles that wouldn't
drop
> > down to the same RPM consistently.
[SNIP]
Then Phil Pick wrote:
> Not an available part here in UK any more. I believe a common
> mod was to use the springs from the BSA/Triumph single cylinder
> B25/B40/B44/B50 models. Was that the case?
>
> If anyone has a sample (unused) of the recommended stronger spring
> I'd like to get some produced........
>
> regards:
>
> --
> Philip Pick
Didn't the Trident/R3 use heavier springs due to them having three sets of points rubbing blocks to overcome going back to idle?
John Mead
Date: Wed, 17 Jun 1998 10:27:29 +0100
From: Philip Pick
On Tue 16 Jun, John Mead wrote:
>>On Tue 16 Jun, Tom Davenport wrote:
>>> Certainly Art X has a point re: replace stock unit with Boyer,,
BUT: Sonny
>>> Routt isn't the only one who used the heavy duty springs on AAU's
as that
>>> was a well known manoeuvre in the 70's for curing idles that wouldn't
drop
>>> down to the same RPM consistently.
>>>
>>> In fact, I was so impressed by it that I have a Lucas parts envelope
from
>>> some of those sitting in my toolbox at home (can post the Part
Number on
>>> Saturday unless Phil Pick or someone has it more handy) as a ready
>>> reference, even though I personally do not ride a bike needing
that mod.
>>
>>
>> Not an available part here in UK any more. I believe a common
>> mod was to use the springs from the BSA/Triumph single cylinder
>> B25/B40/B44/B50 models. Was that the case?
>>
>> If anyone has a sample (unused) of the recommended stronger spring
>> I'd like to get some produced........
>>
>> regards:
> > Philip Pick
>
> Didn't the Trident/R3 use heavier springs due to them having three
> sets of points rubbing blocks to overcome going back to idle?
>
> John Mead
John.
Not having any original samples or access to any Lucas records I can not answer that question. However from the parts books I've gleaned the following list of part numbers.
Any further information would be much appreciated:
Auto Advance Springs, part numbers
regardsT25 54417992
4CA Twin 54415642
6CA twin 54415642
10CA (T140) Twin 54412229
Triple 60600459
Philip Pick
Date: Thu, 16 Jul 1998 16:12:17 -0400
From: Dave Quinn
There are a bewildering number of advance springs available, for a bewildering number of applications.
I have in stock a dwindling number of part #54417992- these are the
Sonny
Routt springs that Art mentioned in the previous thread. Have had great
success fitting these to Triumph twins. Fitting two springs saps performance,
so I only fit one. You can either fit a stock spring to the other side
or no spring, it doesn't make any difference.
With one heavy spring fitted there is a definite step and the bike comes on the cam nicely at between 3500 and 4000 rpm- haven't paid closer attention- the bike just doesn't rattle. Standard ignition advance springs seem to give full advance below 3000 rpm. This is why the bikes rattle, the octane in the gas isn't high enough to stand that kind of advance that early.
Heavy springs doesn't give you anything until about 5000 rpm if you can coax the motor up that far, and the bike is really flat. 2 springs is the way Routt sold them and for a long time I thought I had been sold a pup, so to speak.
Necessity being the mother of invention, I tried just one spring (I know it sounds crazy) in desperation and it really works. Low tech and flying by the seat of your pants, the way I like it. I have a heavy spring fitted to every twin I ride.
Since I can now see the bottom of the parts bin, I have passed on a sample of the spring to a customer of ours who knows a guy who has a spring winder, and he has made a _pile_ of them. I haven't tried one out, but plan to shortly. If they are up to the job I'll let the list know. We've also promised a sample to Phil Pick when next he visits- perhaps he'll make some up too?
Dave Quinn
Date: Wed, 15 Jul 1998 19:18:54 -0000
From: C. Arthur Xanders
We had a thread on here about heavy duty advance springs. I searched around for some, to little avail. John at Coventry told me that he had sold his in a batch lot long ago. A lot of other sources came up bare. Today I got a flyer from a supplier that lists:
54415642 Heavy duty advance spring set for auto advance 1963 to 1978!!!!!!!!!!!!
If you want one or more sets of these, e-mail me privately and I'll work up a single set price as well as some quantity deals!
Art X
18.2 Ignition Points Capacitors.
Date: Thu, 11 Jun 1998 10:23:58 -0700
From: Mel Ray
A brit-oid very kindly and gently pointed out that my spec of 2200 mf for an ignition cap was missing the decimal- so right, Mr mutt, .22 is more like it.
I'd need the FHH (special Triumph tool) to make enough room in there
for 2 or 3 2200 mf caps- they're about the size of a 16 oz beer can.
--
Mel Ray Nottage
Date: Sat, 8 Aug 1998 01:12:54 +0000
From: Trevor P Hodgkinson
Boy, this is going to be a biggie.
I will try to be short.
A coil is simply a device for rearranging energy, in particular electrical energy.
Remember old Newton, energy can be neither created nor destroyed. In the case of an ignition coil, the "power" is a fixed function of the relative number of windings of the primary & secondary coils. The amount of gap that a spark can jump is controlled by the voltage of the spark.
The higher the voltage of the spark the bigger gap it can jump. Very roughly, if a 30,000 V spark jumps a gap of 10th and a 60,000 V spark jumps a 20th gap. If you connect the 60,000 V coil to a 10th gap, it will start to jump when the potential reaches 30,000 V, but it will spark for twice as long as the 30,000 V coil would if it was connected to the same gap. To your eyes it appears as a "bigger", "fatter" spark. The down side is that the Big coil would draw twice as much current as the small coil, or take twice as long to energise. In reality it is a combination of extra current and extra time. The extra current generates extra heat energy which it "steals" from the available spark energy while the extra time required for each spark to be created reduces the maximum number of sparks per minute that the coil can convert, and thus limits the maximum RPM.
This is what happens with 2 x 12v coils on the end of a Boyer. At high
revs the primary windings do not fully energise so that when the points
open the depleted spark may not have enough potential to jump the gap and
the engine misfires. On the same topic this is why all of those "ignition
boosters" can not do what their manufactures claim, unless they have an
external power
supply. Many years ago it was a common practice to cut the HT leads,
poke a brass button in both ends and then put them in a glass / plastic
tube about 1/4 inch apart. This apparently gave a stronger spark at kickover
speeds, but in reality just turned more "sparks" into wasted heat.
As to running increased plug gaps, this is to a large extent a self defeating exercise. Yes you will get a better spark at idle speeds at the cost of reliable spark at revs.
Bike Beesa
Trevor