AMC Gearbox Kickstart Bush

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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George Kaplan
Posts: 160
Joined: Tue Apr 25, 2017 1:24 pm
Location: York

AMC Gearbox Kickstart Bush

Post by George Kaplan »

I am rebuilding my gearbox and there is too much play in the kickstart shaft bushes.

I have bought one new one for the outer case but the inner case bush is out of stock with the usual suppliers.

No problem I will make one. I have removed the old bush and spark tested it and it seems to be iron rather than steel.

My question is does it matter so much is this bush is made of steel?

I am aware of the self lubricating properties of cast iron but given that this bush is immersed in oil and also the fact that the wear on it will be minimal, (ie.only a part of a turn every time the bike is started and in between nothing) then is iron really needed? Or would steel be OK. I only ask as I dont have any iron in stock of the right size. If its essential I could buy some but what do you think?

Also, does anyone know what the recommended clearance is on these bushings? Again I don't think its critical given the application and environment but if there is a recommendation i would like to use that as a starting point.

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Thanks,

John
Greybeard
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Joined: Mon Jun 29, 2015 8:49 pm
Location: East Yorkshire

Re: AMC Gearbox Kickstart Bush

Post by Greybeard »

John, what size is the O/D of the bush? I have a foot length of cast iron bar that is 42mm diameter. I live in Skidby so not a million miles away from you, if it's of any use. You'd be welcome to take what you need and let me have the rest back - or I can hacksaw you a length off and post it to you if needs be. It's the sort of job that could keep me occupied in the workshop for an hour or two :?

Steve
George Kaplan
Posts: 160
Joined: Tue Apr 25, 2017 1:24 pm
Location: York

Re: AMC Gearbox Kickstart Bush

Post by George Kaplan »

Hi Steve, Thanks for the offer, its most generous of you. The max OD is 1.5" so 42mm is more than enough.

However, I would hold off with the hacksaw whilst i mull it over. Since posting this I have been pondering just buying a decent length myself as its the sort of stuff that I am sure I would use more of in future.

If I need a piece I will let you know. Either way thanks very much for the offer.

John
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1608
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Location: ESSEX UK

Re: AMC Gearbox Kickstart Bush

Post by 1608 »

If the outer bush is steel then I don't quite see why the inner should be any different. You say you've been unable to obtain said bush but have you confirmed that the original would be cast. As you say, the use the bushes would get suggest that the clearances are not crucial. If there is wear on the k/start shaft then making your own makes sense. As I'm sure you know a worn shaft/bush will cause accelerated wear of the seal.
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