Author Topic: Fitting new layshaft bushes  (Read 1327 times)

Offline Steverat

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Re: Fitting new layshaft bushes
« Reply #30 on: 26.11. 2018 14:47 »
Thank you so much. I’ll do the donation immediately I get in tonight.
...Made the donation..

1951 BSA A10 - now returned to Germany
1972 Triumph T100R Daytona
1924 B-S SS80
1965 Triumph SH Cub
1960 AJS M18CS

Offline Steverat

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Re: Fitting new layshaft bushes
« Reply #31 on: 01.12. 2018 22:44 »
Found out I was using the kickstart ratchet pinion sleeve washer instead of the proper 0.093" layshaft thrust washer. So now with the correct item in place I have a pinch (negative endfloat). Busy cutting gaskets to get a bit of endfloat and a nice free running layshaft. Or would it be okay to leave the (thinner, 0.060" but also hardened) kickstart washer in there?

1951 BSA A10 - now returned to Germany
1972 Triumph T100R Daytona
1924 B-S SS80
1965 Triumph SH Cub
1960 AJS M18CS

Online berger

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Re: Fitting new layshaft bushes
« Reply #32 on: 02.12. 2018 00:15 »
no build it correctly gaskets will give you a bit of clearance and fit the washer with the chamfer to the splines

Offline duTch

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Re: Fitting new layshaft bushes
« Reply #33 on: 02.12. 2018 06:38 »

 Yeah- What bergs said..... emphatically......I didn't think they interchanged anyway
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online muskrat

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Re: Fitting new layshaft bushes
« Reply #34 on: 02.12. 2018 08:06 »
G'day Steve.
I found with my plunger box if I used a thicker gasket between the case and inner cover I had problems with the claw not engaging with the cam plate properly. I've heard others with similar results. Double check the blind bush is all the way home.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Steverat

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Re: Fitting new layshaft bushes
« Reply #35 on: 02.12. 2018 08:20 »
Wise words thank you all. I may turn a bit of the end face off the blind b if indeed it. Is fully home

1951 BSA A10 - now returned to Germany
1972 Triumph T100R Daytona
1924 B-S SS80
1965 Triumph SH Cub
1960 AJS M18CS

Online Greybeard

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Re: Fitting new layshaft bushes
« Reply #36 on: 02.12. 2018 08:35 »
Steve. You should read this:

After completing the reassembly of my gearbox and engine I was gutted to find that gears were not selecting properly. Oh boy I was not happy to think that I'd have to take the engine out again! I spoke to Richard Clamp who'd renovated the box. He said that he had fitted a gasket on the inner case because there wasn't one on the box as I'd taken it to him. I had a feeling that I'd read something on this forum about plunger gearbox gaskets so I searched the forum and from various posts I could identify that I probably had the same symptoms. With Richards agreement I stripped off the gearbox covers and quickly refitted them with no gaskets. Gear selection immediately felt positive. I cleaned off the old sealant, applied Blue Hylomar to both sides, waited for it to dry a bit, reassembled the covers and took the bike for a run. The gearbox is now GREAT!
Richard Clamp has been as upset about this as me. He even offered to drive down and take a look at the box on the machine.

A couple of things:

1) A theory about the notorious problem associated with inner gearbox case gaskets on Plunger models (I don't know if this applies to swinging arm models)

I was pondering why the presence of the gasket should make a difference to the selector arm claws. I reckon the problem is because the selector arm being pivoted the claws move in an arc toward the selector cam slots. As the claw approachs the edge of the selector cam slot they must be very close to the top edge of the slot. The gasket thickness must be enough to cause the claw to collide with the cam rather than going right into the slot. When the claw is properly positioned into the slot I'm sure there is really good contact. I've made a drawing to try and show my thoughts on this.

2) When adding oil to your gearbox do not stop when a little oil comes out of the level plug. The level plug is in the outer case which fills quicker than the main gearbox casing. Wait for the oil to stop dripping and then add some more, wait a while, add some more etc. until a real stream of oil issues forth from the level plug hole. I'm pretty sure that that is how I allowed my gearbox oil to become so low.

Offline Steverat

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Re: Fitting new layshaft bushes
« Reply #37 on: 06.12. 2018 07:00 »
Ian,
Thanks for that. I pulled the gasket out, had the thrust washer thinned down by 0.020" to 0.073" and did another trial assembly; suddenly the box indexes up and down much more freely, turns with no tight spots. Thats with the dogs and splines practically bone dry from all the handling, too. I may have taken a bit too much off the thrust washer, the layshaft end float is a bit clunky, may be ~0.010" to ~0.015" now. But I'm thinking thats not so bad - both bushes at the ends of the shaft have generous thrust faces with slots in them to let oil pass out, and the only constant end load is going to be from the skew gear which drives the speedo, which I'm guessing will not have much force. Perhaps I'll butcher another washer to try and get the endfloat to zilch, but I'm not sure its worth the bother.
Steve

1951 BSA A10 - now returned to Germany
1972 Triumph T100R Daytona
1924 B-S SS80
1965 Triumph SH Cub
1960 AJS M18CS