removing gearsets

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nortoncavortin

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Apr 19, 2014
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I am working on replacing the layshaft bearing in my 1969 Commando. I am trying to do it while the gearbox is on the bike following the procedure at http://www.doov.com/apps/nortoncomp...t&view=article&id=25:layshaft-bearing-upgrade. I successfully removed the outer and inner gearbox cases. The first gear on the layshaft pulled off pretty easily, but I can't get the first mainshaft gear or second layshaft gear to budge. Is there a secret to getting these gears off?
 
IIRC there's a thin long threaded shaft the shift dogs pivot on that must come out before dogs free to allow the rest of the cog to about fall out too. Do not mix up which way each cog faces as at least one set I forget which can go on either way but of course only works one way, after all buttoned up, ugh. I can't find the shifter dogs nor their pivot shaft shown in my hard copy manual or online but it screws into DS of shell and is ~3/8" dia and 6 inches long with end flats to torque on.
 
L.A.B. should set up subscription to view his manual error corrections and expansion of manual's over sights. Would be a type of blackmail but for newbies and forgetful seasoned folks a win win.
 
The dog shaft has milled flats on the end for a wrench and it unscrews from the rear of the box. I had exactly the same issue when I did mine a few months ago
 
That was it -- I needed to unscrew the dog shaft.

Now, the bearing I see is labeled Hoffman England. So it's not the Portugal, but it's also not one of the replacements I've ever heard of. Is this an original part?
 
nortoncavortin said:
Now, the bearing I see is labeled Hoffman England. So it's not the Portugal, but it's also not one of the replacements I've ever heard of. Is this an original part?
Click to expand...

Hoffman (or, Hoffmann) later became part of Ransome, Hoffmann & Pollard, or: 'RHP'.

http://bearingshoffmann.co.uk/history-o ... rings.html

Regardless of the maker, any standard steel or brass cage 6203 layshaft ball bearing should be replaced, either with the NJ203E roller bearing, or the 'Mick Hemmings' 6203TB P63 FAG phenolic cage ball bearing.
 
Thanks, so definitely replacing it. I feel like I should replace the other bearings while I'm in there.

So I tried heating the casing to 200 and pulling out the bearing with the shaft with no luck. Is there another trick or tool for getting the bearing out or do I have to pull the gearbox off the bike at this point?
 
nortoncavortin said:
So I tried heating the casing to 200 and pulling out the bearing with the shaft with no luck. Is there another trick or tool for getting the bearing out or do I have to pull the gearbox off the bike at this point?
Click to expand...



Try more heat, as, in this instance, 200 degrees isn't quite enough.
 
Did the shaft come out? I put a heat gun in there set at 450 deg F for like 10 min aimed at the back of the case. The whole shaft bearing and all came right out. The trick is to use enough heat quickly as the aluminum case expands faster than the steel bearing. If you heat soak everything the bearing will expand too much to slip out of the bore

Once you get it out lever the bearing off the shaft while it's still hot
 
Having your layshaft bearing stuck is not a bad thing. It means that your races are in good shape.

I am assuming you mean 200c and not 200f.

If you can get the shaft out, leaving the bearing behind (which I believe as it should be) you will then need a blind bearing puller. With this item you may still want to heat up the cases to reduce any wear to the machined surfaces from disassembly and assembly.
 
pete.v said:
If you can get the shaft out, leaving the bearing behind (which I believe as it should be) you will then need a blind bearing puller.
Click to expand...


However, the bearing is usually a reasonably tight fit on the shaft, which does at least make bearing removal easier.
 
nortoncavortin said:
Thanks, so definitely replacing it. I feel like I should replace the other bearings while I'm in there.

So I tried heating the casing to 200 and pulling out the bearing with the shaft with no luck. Is there another trick or tool for getting the bearing out or do I have to pull the gearbox off the bike at this point?
Click to expand...


Even after lots of heat mine layshaft bearing was still fixed firmly in the case. So as I didn't have a blind bearing puller and do have a MIG welder I heated the case then weld a 12mm nut to the bearing then with bit of threaded rod screwed in with nut at other end an large socket on rod I had a makeshift slide hammer. The weld held as you don't have to apply large amounts of force because it is acting straight on the bearing in the direction you want just keep cases hot as you do it.
 
pete.v said:
If you can get the shaft out, leaving the bearing behind (which I believe as it should be) you will then need a blind bearing puller. With this item you may still want to heat up the cases to reduce any wear to the machined surfaces from disassembly and assembly.
Click to expand...

Thanks! A new tool I can manage.
 
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