Gearbox layshaft bearing replacement

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Steves

Steves

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So the gear box broke. Usual symptoms starting with Kickstarter tapping back of the leg, then noise etc.

Initial thought layshaft bearing. Further Initial thoughts are to do it with gearbox in the frame, if however I need to take the main shaft out is that going to create a problem in being able to dismantle primary drive. I suppose I could loosen everything up on the primary side in anticipation, but leave in situ.
 
When Steve helped me replace my layshaft bearing, we did it with the gearbox still in place.
Just the bearing replacement would have been somewhat easier out of the frame, but the gearbox removal and replace is itself rather tedious.
 
I did it in the bike with no problems. I would recommend buying or making a clutch lock tool. It can be made by bolting an old plain plate and friction plate together. The store bought one has a really long handle that can rest on the rear iso thru bolt nut. Nice! I think it is from Andover. I replaced my mainshaft and sleeve gear bushes also. It was bent with a twist to it so unfixable. I had the transmission gears and layshaft out before deciding to go all the way so needed the tool to take the primary apart.

Russ
 
Thanks guys, ended up stripping it down in situ this afternoon. All pretty straight forward, ordering parts.
 
Heat and cold alone were oblivious to my needs when I wanted to replace my layshaft bearing this summer, I ended up cooking up a home-made slide hammer: be prepared for some creativity in removing the old bearing, point being not to give up, it can be done! I tried removing the gearbox, but that proved to be such a PITA that I shall henceforth do all gearbox work with the box in place, unless it's the box itself that needs replacing ...
 
i think the manual states to put up the are then drop the case. clearly they had never had to do one that wouldn't come out.
i made up a puller to extract mine
 
So yeah heat and a threaded bar with bits added did the trick. So last question on this matter, I have done some research there seems to be pros and cons re ball or roller bearing replacement.

The bearing (layshaft) I took out has done about 10k miles. It's a caged ball bearing with a half shield, FAG, it looks in good nick until you spin it then it sounds like a bag of nails and feels notchy.

What it is the opinion, roller or ball?
 
If a ball bearing (my preference) it should be a FAG 6203 TB P63.
 
Steves said:
So the gear box broke. Usual symptoms starting with Kickstarter tapping back of the leg, then noise etc.

Initial thought layshaft bearing. Further Initial thoughts are to do it with gearbox in the frame, if however I need to take the main shaft out is that going to create a problem in being able to dismantle primary drive. I suppose I could loosen everything up on the primary side in anticipation, but leave in situ.
Click to expand...

Much easier to do out of the bike. You can heat the entire box on a gas grill or in the oven to remove and install bearings.

I used the upgraded FAG roller bearing when I did mine
 
L.A.B. said:
If a ball bearing (my preference) it should be a FAG 6203 TB P63.
Click to expand...

L.A.B., what is your rationale for preferring balls over rollers?
I'm not disagreeing, just interested as this is a job I will do on my 650SS soon.
Cheers
Rob
 
robs ss said:
L.A.B., what is your rationale for preferring balls over rollers?
I'm not disagreeing, just interested as this is a job I will do on my 650SS soon.
Click to expand...

Mick Hemmings recommends the FAG 6203TB P63 phenolic cage ball bearing over the roller as he says (in the NOC Norton Gearbox Servicing video) that he's never known one to fail even under racing conditions. The ball bearing often doesn't require shimming, unlike the roller.

Mick's own words from the NOC video:
......The bearing that I prefer [showing the TB ball bearing to the camera] is a very very special ball bearing, I've been using this for *twenty* years, and it's been used by everybody from Wayne Gardner to Barry Sheene in all the six-speed gearboxes I build, and 'touch wood' we've never had a failure yet, so that is the bearing that I prefer to use...."
Click to expand...

*(Must be getting on for around thirty years by now)

https://www.123bearing.co.uk/bearing-62 ... 63-FAG.php
 
So I ordered the ball bearing from Mick Hemmings, took about 4 mins of pleasant conversation on the phone. I tried that 123 bearing outfit, about 15 mins of confusion (I didn't want to register on the website) on the telephone, it's based in France.

There are some good threads on here about the layshaft bearing, plus some good how to's on the inter web.

I am wondering whether to offer up the bearing on the shaft to the gear box or bearing in first then shaft. I don't have a problem freezing the bearing but would not want to apply much if any heat to it.

Will play around with it when it arrives, but thoughts?
 
Steves said:
So I ordered the ball bearing from Mick Hemmings, took about 4 mins of pleasant conversation on the phone. I tried that 123 bearing outfit, about 15 mins of confusion (I didn't want to register on the website) on the telephone, it's based in France.
Click to expand...

The 123 site was just to show an example of the bearing.


Steves said:
I am wondering whether to offer up the bearing on the shaft to the gearbox....
Click to expand...

That's how Mick does it in the video, and how I did it, that was sometime before I watched the video.
 
I found that 123 site independently of your link, so into habit of Googling stuff it can, if not careful, lead you up the garden path.

And thanks will try it on the layshaft and then into case.
 
When doing the laysahft bearing on a gearbox with 12,000 miles, is it best practise to just perform the full overhaul with all new bushes, springs, seals, bearings or is it quite reasonable to just go after the layshaft bearing and resuse existing components save for seals/gaskets?
 
Steves said:
So I ordered the ball bearing from Mick Hemmings, took about 4 mins of pleasant conversation on the phone. I tried that 123 bearing outfit, about 15 mins of confusion (I didn't want to register on the website) on the telephone, it's based in France.

There are some good threads on here about the layshaft bearing, plus some good how to's on the inter web.

I am wondering whether to offer up the bearing on the shaft to the gear box or bearing in first then shaft. I don't have a problem freezing the bearing but would not want to apply much if any heat to it.

Will play around with it when it arrives, but thoughts?
Click to expand...
Freeze the bearing. Heat the case area with a heat gun. Work quickly before the 2 equalize temperatures from their mutual contact.
 
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