Layshaft BALL Bearing Upgrade - "in situ" - Techniques And Tips Help?

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Kip

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My winter project is to update the Layshaft bearing using the (Hemmings recommended) BALL bearing. All the bazillion threads on this site and elsewhere have been a great help and education - BUT - there are still details about which I'd like to have more input before I get in too much trouble with this job.

I would much rather do it "in situ". The thing is, there does not seem to be any step-by-step, pic-by-pic, article or video that shows how it is done. (I'm aware of the Hemmings video, but since it is "bench work" and deals with an overhaul, it isn't focused specifically on simply swapping a Layshaft bearing.)

The Norton Companion has (to me) the most comprehensible basic instructions SPECIFIC to the layshaft bearing "in situ", without muddying the water with additional rebuild tasks, but it involves the roller bearing upgrade rather than the ball bearing.

So... apropos the BALL bearing install, is it best practice to heat the bearing, freeze the shaft, assemble them, and install them together in the (heated) case - or - heat the case, install the bearing, then freeze the shaft and install the shaft in the bearing?

Is anyone with experience, willing to provide a "Norton Companion" type of instruction on how to do an in-the-bike Ball Bearing Layshaft Upgrade alone? It sure would be helpful - and reassuring to those who have never tackled a thing like this before. (Hint!-Hint!)

Thanks in advance for any and all tricks or tips to make this job go smoothly and end well.
 
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Freeze the bearing . Never - ever heat up a bearing . Heat the box up with a heat gun at the layshaft back where the frozen bearing will go in , gently tapped in squarely on the main outer race only , never the inner . Sometimes it just pushes home . Heavy leather gloves . Same to to get the old original out of the box . First and beforehand .
Personally I do the roller layshaft bearing fix . but who needs an engineering argument . Good luck , don't forget to shim the layshaft from the kicker end a la Old Britts article .
 
Torontonian - so when installing the layshaft after the bearing is installed, should it be a snug 'slip fit' as Hemmings remarks? If it isn't -what then? Freeze the shaft and hope for the best or..?
 
Yes the layshaft should slip fit into the new bearing with a dab of gearbox oil no problemo . You can test the fit beforehand . Bearing onto layshaft .
 
Kip said:
Torontonian - so when installing the layshaft after the bearing is installed, should it be a snug 'slip fit' as Hemmings remarks? If it isn't -what then? Freeze the shaft and hope for the best or..?
Click to expand...

Other knowledgeable experts have said a slip fit isn't necessary so you can simply pull (or lever) the old bearing off and press the new bearing on and no need to ease the shaft as Mick said unless the new bearing is very tight.


Kip said:
The Norton Companion has (to me) the most comprehensible basic instructions SPECIFIC to the layshaft bearing "in situ", without muddying the water with additional rebuild tasks, but it involves the roller bearing upgrade rather than the ball bearing.
Click to expand...

The procedure is basically the same for the ball bearing as it is for the roller only the complete bearing is fitted to the shaft instead of the roller inner race. A bearing puller isn't absolutely necessary.
 
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Torontonian said:
Freeze the bearing . Never - ever heat up a bearing . Heat the box up with a heat gun at the layshaft back where the frozen bearing will go in , gently tapped in squarely on the main outer race only , never the inner .
Click to expand...

The ball bearing, however, would usually be fitted onto the layshaft first and then the layshaft used as the fitting tool and if the case is hot enough it should slide straight in, so no point freezing the bearing.

The FAG6203TB ball bearing has a phenolic cage so probably best not to heat it (much).
 
I did my gb following the Hemminngs DVD, using his phenolic.when ordering the bits from him on the phone, he convinced me to not just do the layshaft, but do all bushes, bearing, springs and seals while there. He kept saying i was only doing half the job with layshaft bearing alone. Meant having to pull primary off to remove drive sprocket and get the output shaft out. Gave up trying to get gb out of engine plates and just proceeded doing it all in situ. Was not a difficult job, just took my time, triple checking things.
During the work, found the kicker ratchet worn and the clutch lever arm badly worn where the ball bearing sits. So having all the rebuild parts on hand was a blessing.
 
Tornado said:
I did my gb following the Hemminngs DVD, using his phenolic.when ordering the bits from him on the phone, he convinced me to not just do the layshaft, but do all bushes, bearing, springs and seals while there. He kept saying i was only doing half the job with layshaft bearing alone. Meant having to pull primary off to remove drive sprocket and get the output shaft out. Gave up trying to get gb out of engine plates and just proceeded doing it all in situ. Was not a difficult job, just took my time, triple checking things.
During the work, found the kicker ratchet worn and the clutch lever arm badly worn where the ball bearing sits. So having all the rebuild parts on hand was a blessing.
Click to expand...
Using their best stupidity, Norton made the cradle so the gearbox could easily come out but also made the cradle so the engine interferes with taking the gearbox out. If you remove the three cradle to engine mounting bolts and push the engine out of the way, the gearbox will come out. IMHO, the gearbox is MUCH easier to work on when on the bench - especially when changing the bearings.

I always replace all three bearings and any suspect springs; however, I consider it bad practice to replace any bushing that is running well on its shaft. Gearboxes have much more to break-in than engines! Putting new bushings on broken-in shafts is not good IMHO. On the other hand, if changing a shaft, I usually replace the related bushings.
 
Well, while not unanimous, this information points in the right direction....thanks!

I'm a charter member of the "Better to have it and not need it than need it and not have it" School of Parts and Tools Supply. So, while I do not anticipate additional issues, I have accumulated "stuff" to help...in case.

I'm also reluctantly willing to admit that Murphy is in charge which could mean stuff I don't have and might still need.

Then there's the eternal question: "Why is there never enough time to do it right and always enough time to do it over"? When I said this was going to be a winter project, it was with this reality in mind.

I do NOT want to leave any grenades (pin pulled or otherwise) in the box when this is done. After all, failures like this in a car mean pulling to the shoulder and calling a tow truck at worst. On a fifty-year-old motorcycle, it would be the least bad of all possible outcomes.
 
My opinion on freezing the bearing. It is better to warm the bearing not more than you can handle with a bare hand.
The reasoning...first. measure the bearing at room temp. Then put it in the freezer for a couple of hours. It will be about 29 or 30 degrees. Measure again, there will be no shrinkage. If no change in O.D. then there is no use in freezing the bearing. The downside of freezing the bearing: when the frozen bearing touches the hot case the case VERY QUICKLY contracts around the bearing (like slamming the door) making it difficult to install unless the alignment is perfect.
Warming the bearing gives more working time for installation.
 
Kip said:
My winter project is to update the Layshaft bearing using the (Hemmings recommended) BALL bearing. All the bazillion threads on this site and elsewhere have been a great help and education - BUT - there are still details about which I'd like to have more input before I get in too much trouble with this job.

I would much rather do it "in situ". The thing is, there does not seem to be any step-by-step, pic-by-pic, article or video that shows how it is done. (I'm aware of the Hemmings video, but since it is "bench work" and deals with an overhaul, it isn't focused specifically on simply swapping a Layshaft bearing.)

The Norton Companion has (to me) the most comprehensible basic instructions SPECIFIC to the layshaft bearing "in situ", without muddying the water with additional rebuild tasks, but it involves the roller bearing upgrade rather than the ball bearing.

So... apropos the BALL bearing install, is it best practice to heat the bearing, freeze the shaft, assemble them, and install them together in the (heated) case - or - heat the case, install the bearing, then freeze the shaft and install the shaft in the bearing?

Is anyone with experience, willing to provide a "Norton Companion" type of instruction on how to do an in-the-bike Ball Bearing Layshaft Upgrade alone? It sure would be helpful - and reassuring to those who have never tackled a thing like this before. (Hint!-Hint!)

Thanks in advance for any and all tricks or tips to make this job go smoothly and end well.
Click to expand...
I used to grind the odd shaft for a hardened Torrington sleeve on our crankshaft grinder, they only have about 2 tenths interference, I was taught to fit them buy just sitting the sleeve on a lead light bulb for a minute or two , they just drop on .
 
The RGM supplied bearing is size for size (17 mm on 17 mm) so is not going to take a lot of heat or a 100 ton press to install on shaft end.

You would still have the massive end float (at least 1mm / 0.040") at the opposite side of the shaft. I did of course machine aluminium bronze thrust rings with a bevel at the outer ID to suit the fillet radius at the kick start splined output.
Isolastic shims could be used but are far from a decent fit (compared to a machined one piece ring)

I can't imagine any good reason to make that job difficult (in the bike) , that being time to remove the box and do it on the bench when there are other things to check verses projected riding hours once back in service compared to actual servicing time. (fix hours / ride years)

Why do I have a brand new unused RGM sourced bearing because I used AN sourced roller bearings.

Layshaft BALL Bearing Upgrade - "in situ" - Techniques And Tips Help?


 

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