The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: coater87 on 07.03. 2016 06:05
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I need to make new bushings.
I have the material to make these steel, bronze, etc. I wonder if BSA used steel because of cost and knowing there may be a lack of maintenance here, or they felt bronze would not hold up well enough in these areas with the odd shaft motions.
What has held up for guys?
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I have made them in stainless. They're in for a couple of years now and seem to hold pretty well. No sign of wear on the shifter or kickstarter shaft neither. Made them to the tightest tolerances possible to avoid oil leaking out.
I think softer stuff like bronze would wear out quickly. The ones that came put where plain steel and had a lot of oil leaking by.
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Morris,
Stainless is one thing I dont have in large enough sizes. *sad2*
I have decided to turn them out of 41L40, and give that a try. Its a weird material, leaded high strength steel that can actually be hardened if you want. Plus, I have it on hand.
Lee
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If the bush material is too hard or wrong composition, will there be a risk of wearing the shaft first?
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I don't think so in this case Dutch. This is super slow rotation, and mostly not even a full rotation at that (shifter).
I chose leaded because it is very slightly self lubricating, but more so because 4140 in any flavor is a very tough material. Of course I will keep the tolerance tight, and make sure they are always lubed. I think it should work fine in this instance.
I could have even used grey cast iron except for possible sideways violence of the kicker and how badly and quickly it rusts.
Lee
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Ok sounds good
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The outer bushes are steel and the inners are bronze. Tomcat is about to replace the bushes on the Super Rocket and has been wondering about cutting the outer bush in half, and slipping in an O ring. Anyone care to comment on this mod?
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Tomcat,
My bushings are all steel, if thats how it came originally or the bronze ones wore out and were replaced with steel I dont know.
Lee
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Hi
I have never come across original bronze bushes on kickstart or gearchange, always steel
I have made new from steel or stainless
I added O rings to a recess on the inside of the bushes
If you totally seal the gearbox it can pressurise in hot weather or on a long run !! so a breather hole becomes necessary *conf2*
John
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a breather hole becomes necessary
ready built in to most BSA bit's *sarcastic*
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Hi Bill,
True indeed *sad2*
John
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The outer bushes are steel and the inners are bronze. Tomcat is about to replace the bushes on the Super Rocket and has been wondering about cutting the outer bush in half, and slipping in an O ring. Anyone care to comment on this mod?
Yep, steel bushes on the inners. I only open my mouth to change foot *conf*
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I only open my mouth to change foot *conf*
LOL *lol* *lol*