Author Topic: B21 kickstart bushes  (Read 441 times)

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Greenfield

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B21 kickstart bushes
« on: 11 March, 2024, 16:11:07 »
As you may gather, I'm getting stuck into getting a B21 deluxe up and running. There is distinct play in the kickstart and in my innocence I removed the gearbox outer cover expecting to find a bush for renewal. There was just a bush for the gear lever which is good. The parts book lists kickstart quadrant bush 65-3116 and cover bush 65-3134. Are these both behind the inner cover?
There was no outer cover gasket, just sealant. Am I correct in thinking that there should be gasket 65-3022? All good fun.

Greenfield

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Re: B21 kickstart bushes
« Reply #1 on: 12 March, 2024, 16:11:34 »
Having bitten the bullet and removed the inner cover, it would appear that the problem lies in the bronze bush inside the kickstart quadrant which I think is part number 65-3116. Can anyone suggest a supplier and how to extract the old one. there's nothing to get hold of. I notice that the parts book lists a quadrant with bush fitted, so that says something! There's also the quadrant oil seal and cover gaskets that are probably obsolete. No gaskets were fitted but I can make a couple of these.

Steve.S

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Re: B21 kickstart bushes
« Reply #2 on: 14 March, 2024, 02:49:54 »
I'm only familiar with the earlier gearbox, but IF it's similar, then the bronze bush in the quadrant is the outer layshaft bush.
There should be a steel bush in the gearbox cover which the kickstart lever runs on, although I've never seen any wear in these. I may be completely wrong about this, but you should be able to see if the layshaft fits inside the quadrant bush to confirm.
 I wonder if you have a mismatch of parts or are you missing the cover bush that the quadrant runs on?
If you feel you need to remove the bronze bush, get a tap 3 sizes under nominal diameter, and use it to cut a deep thread. Then you may be able to grip the end of the tap in a vice and bash the quadrant off the bush. Alternatively you may have to invest in an internal bearing puller and slide hammer, or perhaps drill it out. I wouldn't try removing the old bush until you have a new one.
I think gaskets should be fitted, but you should check mainshaft, layshaft and selector shaft endfloat, if fitting these. Otherwise you will have difficulty in selecting gears.
Hopefully someone with more knowledge than me will give you a better answer.
 

Greenfield

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Re: B21 kickstart bushes
« Reply #3 on: 18 March, 2024, 16:07:25 »
I've drawn a complete blank with sourcing these bushes, can anyone recommend a machine shop that may be able to produce them?
Also, any thoughts on whether the bronze bush would be phosphorbronze or oilite?
« Last Edit: 18 March, 2024, 16:58:55 by Greenfield »

Steve.S

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Re: B21 kickstart bushes
« Reply #4 on: 19 March, 2024, 02:01:15 »
BSA would have used phosphor bronze for the internal quadrant bush, but you could use Oilite if you want.
If you take the measurements of the bush, you may find a suitable oilite bush in one of the Bearing Suppliers lists. Or perhaps one that is close which you can modify?