Crossover shim

[Bandit9]

What role does the crossover shim stack play? I am playing with my base valve stack and I am just learning about stuff and this has me confused.

Thanks

 

[Bandit9]

I meant to say "crossover shim" but I can't go back and edit.

 

[georgieboy]

you haven't done a search on this?
Crossover shims gives the stack above it a free float, untill it hits the stack below. Thicker crossover, more room to bend etc. It is a tuning device for the slower shaft speeds mainly.

 

[bclapham]

shim stacks come in stages- no crossover is a single stage, 1 crossover is a 2 stage stack- it enables the tuner to separate both LSC and HSC (to a degree).

for example, the rm125 has a 2 stage passive valve stack- by swapping the 10.1 crossover to a 12.1 i was able to increase the LSC and leave the HSC somewhat the same.

 

[Bandit9]

Yeah I searched it and didn't really come up with much. Thanks for your replies.