Cometic power valve spacer

[biker]

I'm getting my cylinder back from eric next week. the bike is a 2001 CR 250 and the cylinder is being ported for more low end. I'm going to add the power valve spacer but I'm not sure which one to get. They offer 1) .375" thick
2) .625 thick (will not work with stock pipe)
3) .500 thick
I have and FMF SST pipe, but may go to a gnarly if I can sell the SST. What are the advantages of the different thicknesses.

 

[Wild Hare]

I have the #"2" Cometic spacer on my '00 CR250. It made a difference I could feel, not as good as porting but not bad for a bolt on...

If I had it to do again, I'd look at the Boydsen and Atomic 22 complete covers and ask how much volume they have and if they clear the stock pipe.

FWIW

 

[YoTRacer158]

dirt rider did a complete test w/ somethin like 24 different boltons in an issue not too long ago. one of the items they tested was the powervalve spacer. i'm not positive but i think the thickest one worked the best

 

[Rich Rohrich]

Maybe you should test the engine with the new porting before you make any additional changes.