Portugese layshaft bearing

did exactly the same. Have used the 6203TB bearing in all my rebuilds since. I originally replaced the standard bearing with a 'superblend' roller, but the loss of positive layshaft location was a problem.
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What was the symptom regarding the layshaft position? I have run the C3 roller for years and years but occasionally under hard acceleration the shift ratchet doesn't pick up second gear.
 
Perhaps it is urban legend, but I had read somewhere that this very same bearing is used in the front wheel. Of course in that application it would be packed with grease.
 
Thomasa said:
What was the symptom regarding the layshaft position? I have run the C3 roller for years and years but occasionally under hard acceleration the shift ratchet doesn't pick up second gear.
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I put that many shims behind the kickstart shaft I could no longer get the kickstart to fit without rubbing against the case. There are no thrust faces designed in, and the end float seems to be dependant on the ends of the various bushes or rough machined faces, so not a great solution
 
lazyeye6 said:
Perhaps it is urban legend, but I had read somewhere that this very same bearing is used in the front wheel.
Click to expand...

Yes, the layshaft ball bearing and one (pre-850 Mk3) front wheel bearing were the same (04-0100) part.

Also, one rear bolt-up hub bearing and both (pre-850 Mk3) cush hub bearings.

Now supplied as a sealed 6203 2RS, 06.5542, the 850 Mk3, (one front and one rear) hub bearing.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
 
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texasSlick said:
I keep wondering how many schillings Norton saved by going to this bearing, and the year they did so.
My '62 build Atlas has over 85K miles, and no evidence (kick lever droop) of imminent failure of the bearing.
I also keep wondering how much longer it will last, but I have a Mick Hemmings bearing in stock and first evidence of failure, the gearbox comes out for a rebuild.

Slick
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These AMC gearboxes were used from 1957 onward on 350 single model 50 to all of the Commandos. I would guess it was overlooked as far as stress engineering going from 18hp to over 60hp.
 
Fast Eddie said:
I’d wager the issue was definitely not ‘overlooked’ by engineers … more like requested changes were ‘overruled’ by bean counters…
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....and not the only bike/automotive maker to use a WEAK transmission behind a strong engine.

They work ok if you drive it like a pussy, if you use ALL the engine's power, they fail.

A (partial) list of examples, after I've had coffee.
GM Turbo200 behind a Buick V8
Turbo700 behind a 6.2 diesel
Borg T14 behind International V8
 
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texasSlick said:
I keep wondering how many schillings Norton saved by going to this bearing, and the year they did so.
My '62 build Atlas has over 85K miles, and no evidence (kick lever droop) of imminent failure of the bearing.
I also keep wondering how much longer it will last, but I have a Mick Hemmings bearing in stock and first evidence of failure, the gearbox comes out for a rebuild.

Slick
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Schillings? Not many, they were never legal tender in the UK! We had Pounds, Shillings and Pence. (No, I don't miss them!)

Regarding the bearing. Is this a bit like a game of Russian Roulette?
 
concours said:
....and not the only bike/automotive maker to use a WEAK transmission behind a strong engine.

They work ok if you drive it like a pussy, if you use ALL the engine's power, they fail.

A (partial) list of examples, after I've had coffee.
Click to expand...
Every time I ride my Norton I ride it hard ever since new I have never pussy it from my youth it did burn outs regularly and always riding over the ton and building the hot motor for the Featherbed frame back in the 80s it got ridden even harder and so far the GB has survived with all original gears except for the kick start gear as where the KS pawl sits in the gear wore so needed replacing about 30 years ago, even now that my Norton is semi retired and no longer a everyday rider as it use to be till 2013 and I am more smarter in how I ride but I still don't pussy it.
It is now my hotrod play bike but then it has always been that since I built it back in 82, my motor and GB have well over 160k miles on it and my gear box has never been shimmed, Nortons seem to like a bit of end play in everything lol.

Ashley
 
concours said:
....and not the only bike/automotive maker to use a WEAK transmission behind a strong engine.

They work ok if you drive it like a pussy, if you use ALL the engine's power, they fail.

A (partial) list of examples, after I've had coffee.
Click to expand...
Interesting take. I would suggest the average purchaser of a New Norton did NOT ride it like a pussy, but rode the spit of it.
Every Norton rider I know does just that.....
 
MichaelB said:
Interesting take. I would suggest the average purchaser of a New Norton did NOT ride it like a pussy, but rode the spit of it.
Every Norton rider I know does just that.....
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At age 20 I thought 7000 redline was just where the power came on. New early ‘72 combat roadster. I kept it for 5000 miles…nothing blew up. In my defense the machine before the Norton was a Honda 305 Superhawk.
 
ILLF8ED said:
At age 20 I thought 7000 redline was just where the power came on. New early ‘72 combat roadster. I kept it for 5000 miles…nothing blew up. In my defense the machine before the Norton was a Honda 305 Superhawk.
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Your story sounds like mine. I was 21 when I bought a new '72 combat roadster in April, '72 and my prior (1st) bike was a new '70 Honda CB450 that I got right after I graduated college. Rode the Norton like I stole it for 8,000 trouble free miles over the next 8 years--was never made aware of any combat horror stories. I guess ignorance is bliss and I just got lucky.
 
The loading capability of any ball bearing is very high, much higher than what the layshaft can produce.
If the bearing fails, it is a result of something else such as oil contaminants, heat, corrosion, lack of good lubrication.

Sounds exactly like the evidence of what I've found on the inside of most old AMC gearboxes I've torn down.
 
elefantrider said:
The loading capability of any ball bearing is very high, much higher than what the layshaft can produce.
If the bearing fails, it is a result of something else such as oil contaminants, heat, corrosion, lack of good lubrication.

Sounds exactly like the evidence of what I've found on the inside of most old AMC gearboxes I've torn down.
Click to expand...
Is it not the cage failing that leads to a full bearing failure?
 
It is but just not due to excessive loading or speed, IMHO.

The brass stamped, metal cage is a lot weaker than a steel cage, and less able to cope with the above.
 

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