Good News, Bad News, and Really Bad News!

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yes, I should have rephrased that before hitting post. Is nylon a good alternative would have been more direct?
 
britbike220 said:
yes, I should have rephrased that before hitting post. Is nylon a good alternative would have been more direct?
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Jim already said he didn't think there would be any problem with a nylon cage.
 
I wouldn't get too hung up on avoiding the shims...I would think it important to check the end play of the shaft regardless of the bearing that is chosen and the shimming process is simple.

EDIT...just discovered the above comment is redundant. Good to know I agree with somebody who knows what they are talking about. :)
 
rvich said:
I wouldn't get too hung up on avoiding the shims...I would think it important to check the end play of the shaft regardless of the bearing that is chosen and the shimming process is simple.

EDIT...just discovered the above comment is redundant. Good to know I agree with somebody who knows what they are talking about. :)
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Good to know somebody else agrees. It was common practice to shim the countershaft long before roller bearings ever came into use there. Jim
 
britbike220 said:
So what was the outcome of this bearing fiasco?
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1. replace you layshaft bearing before it fails.
2. use a roller or a ball, your choice, roller lasts longer, ball is cheaper.
3. shim the kicker shaft as per Old Britt's site to prevent trans from popping out of first gear, ball or roller. Jim
 
No, I was wondering if the dude that started the thread actually tore into it and how this turned out for him.
 
britbike220 said:
No, I was wondering if the dude that started the thread actually tore into it and how this turned out for him.
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Good question.

By the way, I did a 850 Mk3 today that was brought to me with the complaint of pops out of 1st gear and see if it needs a layshaft bearing. He had only owned the bike for a short while. It has 17,000 miles on the odo. but I don't know how accurate that is. I pulled it apart and found the case was scarred from a failed layshaft bearing and it had a replacement ball bearing that had been installed sometime back. One of the tangs that held the steel cage together in the new bearing was broken off. I found it in the bottom of the case.
I installed a roller and .040 shim on the kicker shaft. Jim
 
Correction for the last post. After I cleaned the bearing I see it is missing two tangs and the two halves are loose. 2nd failure was on the way. It is a ND bearing , made in USA. Jim

Good News, Bad News, and Really Bad News!


Good News, Bad News, and Really Bad News!
 
comnoz said:
Correction for the last post. After I cleaned the bearing I see it is missing two tangs and the two halves are loose. 2nd failure was on the way. It is a ND bearing , made in USA. Jim

What size gearbag sprocket has the bike been running?
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I'm kind of sceptical about this bearing failure issue overall. I'm am by no means saying there aren't bearing failures at low mileage, but as I've mentioned I have a gearbox with 30K miles on it and have not had a beariung failure. Is it because I take it easy on my old bike all of the time therefore not stressing the bearing? I don't know, but I do know my bike is obviously different than many others for a reason and I doubt I have a special one off bearing. I'm not saying it isn't going to happen today or the next, but why are so many bearings failing on others bikes and I'd be more curious as to how many riders out there have the same longevity as I have? I do know when I do decide to change the bearing, I am going to replace it with what ever is in there now regarless of type because 30K miles seems like a lot better average than what I'm hearing on here. So I'd like to hear from those that are riding happily into 20-30 + thousand miles w/o layshaft bearing failure.
 
I would not use a ball bearing with a steel cage there after seeing that one. The bike presently has a 20 tooth sprocket on it , it also has a performance motor.
I have not doubt a ball bearing is good for more than 30,000 miles. I have seen the brass or plastic caged ball bearings with more than that. If you have an 850 MK3 with 30,000 miles on the original bearing, I would find that hard to believe. Jim
 
bb2200, WTH knows why someone gets wonderful mileage out of a particular Commando component and others' fail very quickly or right out the box?
Consider the conditions of upset labor and worn out machining accuracy and cheapest suppliers with their own internal turmoils affecting products delivered.
Luck of the draw and mood of assemblers. Also may imply you are indeed a limp wrist'd rider so preserving a fine example for the next one to really enjoy using up components and supporting our vital vendors. I'm not saying your mild use is a negative in any way, mostly how I ride too - just enjoying being alive and not being police bait or pressing luck in anyway except of course risk of leaving home on 2 tires only. Frank Forster in NY claims like 100,000 miles on 750 engine gearbox and he's famous for flogging and leading hot shots on serious on and off road rides. Karma? Wyrdness? Astrological vibrations imprinted in alloy melt to resonate gravity waves interfering with the quantum indeterminacy of machining distortion or electron clouds for more oxidation currents of corrosion in grain matrix.

Wyrd is a concept in Anglo-Saxon culture roughly corresponding to fate or personal destiny. The word is ancestral to Modern English weird, which retains its original meaning only dialectally.
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http://en.wikipedia.org/wiki/Wyrd

Good News, Bad News, and Really Bad News!

Good News, Bad News, and Really Bad News!
 
30,000 miles on a mkII bearing wouldn't worry me too much, I would be taking a look when you have an opportunity though. Better safe than sorry. Jim
 
Hobot states:

" Karma? Wyrdness? Astrological vibrations imprinted in alloy melt to resonate gravity waves interfering with the quantum indeterminacy of machining distortion or electron clouds for more oxidation currents of corrosion in grain matrix."

Steve, the above is your best yet. Brilliant! Genius! Insane!

Thank you!
 
comnoz said:
30,000 miles on a mkII bearing wouldn't worry me too much, I would be taking a look when you have an opportunity though. Better safe than sorry. Jim
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I plan on buying a replacement bearing and hopefully will be able to do it this winter. I've never done this task so I am wanting to do it with a clear mind so I can muddle through the process. I really am more curious as to what bearing is inside.
 
The original bearing in that bike would be made in Portugal. It would be the same make that failed in the Mk3 but from an earlier time period. They were not known for catastrophic failure. They usually gave some notice first like noise or kickstarter movement. Jim
 
britbike220 said:
No, I was wondering if the dude that started the thread actually tore into it and how this turned out for him.
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"The dude" that started the thread got off easy.....

I am busy selling my home this month, buying a new one, moving, etc. so have no time to tear into the gearbox myself. Took it to a nearby experienced Norton Mechanic (Steve at North County Motorcycle and Salvage in Escondido, CA) for him to do. He's opened many gearboxes before, and I never have.

The result - the bearing was toast, but did not cause any other damage. All the bushings and gears are in top condition (21,000 miles on the bike) so the layshaft bearing is the only issue - at a parts cost of about $30. It goes back together today, and I'm on the road tomorrow when I get back from a business trip.

Had no idea when i did this initial post that so many people would chime in with thoughts on this topic.

By the way, are there any other "death-defying" (potential) known issues - something that could cause a lock-up while riding????? I'd be glad to take preventative measures.
 
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