Hello
I have a few 40 s and 50s British bikes besides my M20
When I want do a gearbox rebuild I usually purchase bushes and bits from Draganfly in the UK
Either my shafts are badly worn or the bushes are not made to tolerance as the fits are very loose
After reading the tech section I see that 1-2 thou clearance is within spec
If I put my worn shafts on a friends lathe and use his shaft grinder to true them and then make bushes to fit - this would be a better fix
My question is , is phosphor bronze the best material - what grade is best ? I see aluminum bronze and tin bronze and oilite bronze ( sintered bronze ?) are there better modern equivalents ? Do bronze sellers sell tube stock close to sizes we would need
Do I need a slot across the bottom / top of the bush for lubrication - my friend could help with a spiral if that would be the best
A few of the kickstart shafts etc have steel bushings - are these a softer grade steel than the shafts ? What grade steel , does it have to be heat hardened ?
Many thanks for the info
Thanks
Lee
I use PB1 phosphor Bronze for all bushes..The British Standard number for that is BS1400 PB1....You would have to look up a U.S equivalent...Whether you can buy a suitable grade with a 'cored' center (in tubular form) will depend on the U.S material suppliers specs. which I know nothing about...
Regarding the lubrication slots it would be advisable to machine those in as well..'Oilite' is not suitable...
The steel bushes are not all the same spec....The kickstart bush is case hardened and finish ground to size after hardening...The others are not hard and something like an EN 8 grade medium carbon steel (British Standard number 080M40 BS 970) should work OK for those...Check any steel bush with a file to determine whether it is hardened or not...Ian
