Front fork bushes

[a101960]

Right, my forks are now dismantled ready for fitting new shafts and bushes. The new top bushes are only half the length of the old bushes (bushes and shafts bought as a matched set). Now for the inevitable question: will this make any difference? Also just how do you measure the shim gap underneath the circlip? I have bought a pack of shims but I really can't see how this would be done. By the way there were no shims found on disassembly. The good news is that the taper roller conversion was very straight forward and went well so that's half the job done.

John

[alanp]

John, ref the shims, I've never needed them but apparently the check is that you assemble the fork stanchion tube and bushes and circlip, gently punch the top bush down to its lowest position, pull the fork fully out and check to see if clearance between the top bush's collar and the clip causes the bush to move up or clicking can be heard when the lower bush pushes on the underside of the top bush and the bush contacts the clip. It doesn't matter if there weren't any shims on disassembly, it's the collar on the new top bush that matters. 
Concerning the length of the top bush, I have seen a variation of 2" to 2 1/8". If you are saying that you have some at about 1", I wouldn't use them myself.
Hope this helps
Alan

[a101960]

Alan

Not sure of the exact length so will check tomorrow. It is certainly longer than an inch. Regarding the shims I half expected that is what had to be done, which is a real pain because the circlip is a bugger to get out. Still if that is what it takes then it is what I will have to do. Thank you four your input

John

[bsa-bill]

A shortcut is to cut the shims with scissors ( on an angle) this save a lot of assemble disassemble, I'm not sure about this but I found this is what had been done to my fork shims when I dismantled, personally I would prefer shims to be complete OTOH they should not move much once installed and indeed the cut shims in mine had not budged.

All the best - Bill

[chaterlea25]

Hi John,
I'm sure this was covered previously!!
Fit the top bush to the bottom leg before you assemble the fork
use a tubular drift if necessary (shouldnt be) not a centre punch
put in the circlip, then see if yo can insert a feeler guage between the circlip and bush
if you can then you need that amount of shims!!!
remove the bits and assemble the forks with the required shims!!!
DO NOt cut the shims they will work their way out if you do this and probably wreck the seals!!!
If you were sent "short" bushes these are for a "C"11/12 series bike (250cc) and not for A7/10

HTH
John O R

[a101960]

I have now had a chance to measure the top bushes. Overall length of the new bushes = 2.1305" and the top bushes that were fitted originally = 3.5490". So, the question now is: are the 2" bushes O.K. to use on A10 forks, or should they be 3 1/2"? It is interesting to know that the A10 shares certain parts with the C11/12 models. I never knew that, however I am sure that I read some where that the gearbox internals are common to the C12 also. Surely not?

John

[bsa-bill]

Hi John O R - just to clear up a point - I completely agree with you re cutting shims, not something I would do but obviously others do .

anybody got a hint or two about fitting the circlip, I find that part frustrating

As for the gearbox John it could be argued that it is already over engineered for the A/B range let alone the C series

all the best - Bill ( currently bringing a nine foot beech hedge down a peg or two when I should be getting on with the project, the words Forth and bridge come to mind)

[chaterlea25]

HI All,
John You appear to have "Taylor Dow" type extra long  bushes fitted previously
I have not come across these in the metal, only saw a kit for sale on "fleabay"
The 2+in. ones are standard,
The extra long bushes lowered the front of the bike and reduced fork travel!!

On The gearbox questions
The heavyweight C11 gearbox inners "look like" the A boxes BUT ARE NOT!!!
importantly they do not have the same number of engagement dogs which I'm presuming lowers their load capacity
They are also not made from the same steel!!
When I built my SR box I had a long search to complete the cluster in the correct EN36 spec gears
They are stamped EN36, other gears (from memory) could be marked V11 or VIB,this is the code used I believe for a material called "vibrac"
I know Rudge gears stamped V11 are sought after as they are better than the "normal" gears
As far as I can figure out BSA used different spec's either at different times or on different models
When I was searching for the gears, the fact that different spec steels were used was news to all the dealers I contacted!!
In fairness they all searched through their stock to try and find the ones I wanted!
Here endeth today's lesson!!
Regards
John O R

[Richard]

John can I have your old bushes?
Rich