sachs fork valving
- Thread starter dh racing
- Start date
moto9
Silver Level Site Supporter
Try Race tech, I have a whole box of RT shims and I used a dremmel tool with a pointed stone bit and opened up the ID to fit.
Just and FYI - Using a dremel to enlarge the i.d. of the smaller i.d. shims is a rather bad idea.
Les at LT-Racing did a set of sachs forks that were previously revalved by another tuner who did this. When Les disassembled this fork - the dremel'ed shims had fractured and come apart inside the fork . Not sure of the mechanism here - You might start a fracture in the shim without realizing it or the temperature increase while grinding on them may effect the temper of the shims.
Les machines the fork to accept the smaller i.d. shim. This has two advantages - enables use of a more standard size shim. And behavior of the fork is much better - small i.d. shim with large diameter face shim. Ability to control fork with valving is improved. The sachs ends up with the similar characteristic to the newer japanese forks that everyone likes - small i.d. shims with large piston and large face shim...
Jeff
Les at LT-Racing did a set of sachs forks that were previously revalved by another tuner who did this. When Les disassembled this fork - the dremel'ed shims had fractured and come apart inside the fork . Not sure of the mechanism here - You might start a fracture in the shim without realizing it or the temperature increase while grinding on them may effect the temper of the shims.
Les machines the fork to accept the smaller i.d. shim. This has two advantages - enables use of a more standard size shim. And behavior of the fork is much better - small i.d. shim with large diameter face shim. Ability to control fork with valving is improved. The sachs ends up with the similar characteristic to the newer japanese forks that everyone likes - small i.d. shims with large piston and large face shim...
Jeff
twowheels
New member
Jeff, are you saying he was/is using more readily available 6mm ID shims (WP-esque) instead of the 7mm ID Sachs-type shims?
I may have not been clear...
The first set of sachs forks that les did were previously revalved by another shop back east - this shop ground out 6mm i.d. shims to fit 7mm i.d.
When Les disassembled the forks - some of the shims had "come apart" - not good....
And yes, after he is done with the sachs fork - he has modified the sachs fork to employ the more commonly available smaller i.d. shim as well as fixes to other circuits in the fork. He spends a great deal of time on each set and reworks them very completely....
Normally he doesn't like me to say what he does - but given given the difficulty and man-hours required - I sincerely doubt that anyone else will take the time or effort to copy his work on this one...
jeff
p.s. I am "retired" and no longer actively participating in this forum - but when I see someone doing something that could damage their fork and cost themselves alot of $$$ - felt I should say something...
The first set of sachs forks that les did were previously revalved by another shop back east - this shop ground out 6mm i.d. shims to fit 7mm i.d.
When Les disassembled the forks - some of the shims had "come apart" - not good....
And yes, after he is done with the sachs fork - he has modified the sachs fork to employ the more commonly available smaller i.d. shim as well as fixes to other circuits in the fork. He spends a great deal of time on each set and reworks them very completely....
Normally he doesn't like me to say what he does - but given given the difficulty and man-hours required - I sincerely doubt that anyone else will take the time or effort to copy his work on this one...
jeff
p.s. I am "retired" and no longer actively participating in this forum - but when I see someone doing something that could damage their fork and cost themselves alot of $$$ - felt I should say something...
