From: Michael Bishop
Date: Wed, 18 May 1994 05:26:00 -0500 (CDT)
Hello Folks,
Saturday I am going to go look at a '73 Norton 850 Commando, excellent
condition, 6000 original miles, $2500. Ex. cond., low mileage, Where could
you go wrong. Ah! There's the question. What should I be looking for in
the inspection? Does this bike have a favourite place to blow a gasket,
crack the frame, rust solid, etc. Any advice would be welcome.
If everything is as it appears I'll be on a Norton by Monday. $2500 seems reasonable for this bike. Then again I've heard the excellent condition line before.
Yet another subject. I saw an add saying if you bought the bike he would ship it to you for $50 extra. Can you ship an entire motorcycle for $50? How?
M.B.
From: MikeTnyc@aol.com
Date: Wed, 18 May 94 23:42:41 EDT
>Saturday I am going to go look at a '73 Norton 850 Commando....
Unlike brands that had years of flawed frame design and other major problems, all Commandos are basically similar, and there's nothing you can't fix. My '72 Combat, for example, was from the absolute worst year in terms of reliability, and arrived DOA with 3 burned valves -- it had 6000 original miles. The '73, by contrast, already has most of the improvements that I've added, one at a time, to my '72, including the box-section head steady, camshaft bearings that won't frag in the engine, an oil filter, and above all, Superblend main bearings.
Therefore, you're really looking for things you'll have to fix, not some hidden doomsday fault that can't be fixed. Here's some things I'd check:
1. Frame -- loop holding up seat can bend if really heavy loads on passenger seat (e.g. concrete blocks, very fat passengers, etc.) Fix: straighten, and install triangular gussets to reinforce.
2. Isolastics -- put bike up on centerstand and try to move back wheel back-and-forth. It should not feel loose or "clunk" from side-to-side. Vibration from engine should be startlingly pronounced at idle, and diminish markedly at about 2750 rpm. Fix: rebuild rubber mounts, front (easy) and/or rear (hard).
3. Engine -- Check big, finned nuts that hold exhaust tubes on. If their threads in the head are stripped, $100 or so to repair. Engine should start and run fairly easily (for an English bike). Ends of plugs should be a light tan colour. Fix: tune up of some kind. If slides in carbs rattle a great deal, carbs may be worn.
Do a compression test, preferably after engine is warm. Actual figure is less important than that the two cylinders be roughly the same. Significantly lower compression in one means a top end rebuild. Take off points cover and examine auto-advance [if no electronic ignition has been fitted.] If the cam is has much back-and-forth play, it is wearing out, and auto advance will eventually need replacing, preferably with electronic ignition.
4. Engine oil should not look extremely dirty and sludge-filled, nor suspiciously clean, as if just changed. Oil in gearbox should preferably have been gear oil rather than engine oil (check for stinky, sulphurous smell) and should be reasonably clean. Condensation in gearbox is a bad sign.
5. Gearbox -- If allowed, take cover off primary case (owner probably will not permit -- oil will run out everywhere), or take middle plug out of cover. Primary chain should have some sag in it -- if not, it's been straining the gearbox. If pressing down on rear chain w/ your foot causes primary chain to tighten, main sleeve bearings in gearbox is worn. If kick-starter operates roughly, or ESPECIALLY if it moves down on its own when the bike is running, there could be serious gearbox trouble immediately ahead. Fix: rebuild gearbox. [If lever moving down on its own, rebuild gearbox before you ride it any distance.]
6. If owner let you take the cover off primary, take a look at the alternator stator, to see if insulation on wire coming from it is cracked. Handy people can repair/replace this at home.
7. Instruments -- Speedo and tach should work. Rebuild $100 or so, and not do-it-yourself. Veglia instruments on later machines (1973 may have them) are probably not worth fixing.
8. Tires and exhaust -- problems are obvious. Tiny cracks in sidewalls are dangerous.
9. Oil leaks -- all the rubber parts in a 20 year old bike are probably dried out, and the bike will leak some oil. Replace them as you go, and eventually the leaks will be history; it's a bad advertisement for Britbikes to leave puddles behind them.
From: Tony Sumner
Date: Thu, 19 May 94 09:23:39 BST
Check that the pinch bolt in the front fork leg that secures the front wheel spindle has not been overtightened to the point at which the casting cracks.
Cure - new fork slider ;-(
From: Rick Cording
Date: 22 Jul 1994 10:20:31 U
John- I'm no expert, but I do own a '73 Roadster. Here's a partial list of items to check:
General:
* Tire tread (if bad, you'll be $200 out-of-pocket right away)
* Gas tank rust (peer inside)
* Oil tank (any oil inside? Check at the very bottom of tank for oil
leak, often times the mount bolt will cause vibration cracks. No biggie,
but
would require welding/painting)
* Electrics (if you check it out in daylight make sure you try the lights)
* Check front forks for pitting on tubes (if it has rubber boots (gaiters),
ask to loosen and inspect tubes and for seals
Engine:
* Commandos should have good compression. If it kicks over like a H*nda 70 you've got trouble
* Oil leaks. Commandos are pretty oil tight with the exception of slight weeping around transmission seals and primary chaincase.
* Exhaust nuts (at cylinder head/exhaust pipe). Make sure it has 'em and they're tight. These can get easily stripped.
* Carbs. If stock Amals they are probably worn. Check to see if you get an idle.
As with any old thing the more original probably the more worn out. Don't worry though, there are enough parts suppliers and Norton mechanics to practically build new ones from scratch. Good luck!
Rick
From: Nancy J Caputo
Date: Fri, 22 Jul 1994 23:31:54 -0700 (PDT)
Add to list:
With bike on centerstand grasp rear wheel and check for lateral play.
Isolastics my need redoing.
With front wheel off ground check for front wheel play.
If you ride it check for Kickstart movement as you accelerate. If there's
a problem with the gearbox the Kickstart will want to move down.
Have a look at rear sprocket. Teeth in reasonable shape?
Lou TM LUIGI
From: CHLit
Date: Wed, 15 Jun 94 19:01:38 EDT
I found a Norton, but the guy said it was a 75 750cc. Now I don't know what to think. He said it was a limited production model made for racing. I suppose that it was a production run to qualify the 750 for racing. It is supposed to have a hot cam and such. Also it had a right hand shift. It had a 6 digit serial number that I think started with a "9". Is this a bona fide? Or is it smoke from a smoker? BTW, he wants too much(2K) for a bike with no paper.
From: John Kula
Date: Thu, 16 Jun 94 14:40:18 PDT
Norton _did_ make a limited number of 750cc engines for the Mark IIIs. They were basically 850cc engines with a shorter stroke to bring them down to 750cc. Pretty rare beasts, those 750 short strokes. How do you tell? Heh. How well do you know Nortons? But if it's real, $2K would be a deal.
As for the serial number, my microfilms only go up to 1974 -- the official factory records _after_ that date were a total disaster and, besides, nobody seems to know where they got to. But in the series I have, even motorcycles destined for R&D or Proddy Racing still got a consecutive serial number, which should have been in the range of 300,000. That wasn't an "F" at the beginning, instead of a "9", was it?
John Kula
From: Dannysore
Date: Thu, 16 Jun 94 20:00:52 CDT
Norton _did_ make a limited number of 750cc engines for the Mark IIIs.
They were basically 850cc engines with a shorter stroke to bring them down
to 750cc. Pretty rare beasts, those 750 short strokes. How do you tell?
Heh.
Stick a pencil down the sparkplug hole?
From: CHLit@aol.com
Date: Sat, 18 Jun 94 11:26:22 EDT
My memory is going, I think. I can't remember what it was . The number is 209069 no prefix, frame number is the same. It has right side shift, so it's not after'75? John Pinkham reports that this is a 72 Combat Commando w 10:1compression and SS cam. It has the same cyl(flared bottom flange) that my 750 has, so I don't think it's much of a find, since it doesn't run (points advance plate). It does, however come with a cafe fairing and seat(Dunstall?), but no tank.
From: Roy Armstrong
Date: Mon, 01 May 1995 09:22:43 +1000
Russ asked about Norton S/N numbers.
I have a chance to buy a 69 Commando roadster for an (almost) reasonable price. While looking at it, I saw that the usual 6-digit serial number is preceded by '3S'. Is this a high-performance designation, or just normal for that year? I hadn't seen this before on other Commandos I've owned. I couldn't see a number stamped over the exhaust port, but it was pretty grimy, and I didn't look real hard...
I am relying on memory here but Commandos up to 1972 had the 20M3S prefix on the engine but not the frame. I believe the 3S indicated the points were driven from the end of the cam shaft. I have seen a very early Commando with a magneto at the rear of the engine and the tacho drive from the cam shaft, as per the Atlas.
After 1972 the Command Eng and Frame No's were the same with no number or letter prefix.
Someone with a better memory may be able to confirm this or flame me.
From: Charles Falco
Date: Mon, 01 May 1995 08:58:27 -0700 (MST)
On May 1 Roy Armstrong wrote in response to an earlier question:
>...I am relying on memory here but Commandos up to 1972 had the 20M3S
prefix on the engine but not the frame. I believe the 3S indicated the
points were driven from the end of the cam shaft...
According to the records I have, Roy is correct. The prefix on the earliest Commandos was 20M3. Then, starting in '69 (although at different times during the year for different models) when the engine was modified so the camshaft drove the points, the prefix changed to 20M3S. For a '69 Commando the six digit serial number should be 131180 or higher (the '70's start at 135088).
Charles Falco