[strelcheck]

if i put a high compresson piston in my bike. do i have to change out the valve springs or will the stock ones work?

 

[rt]

They'll work fine for any piston, its the cam that ultimately decides if your going to need better springs.
the grinds that'll work with stock springs are
Hotcams stage 1
webcams 461/496 grind

Cams that I'll work with the stock springs, but recommend better ones
webcams 696/697 grind

cams that must have better springs
hotcams stage 2
hotcams stage 3
megacycle x-4
megacycle x-14
webcams 736/737 grind
webcams 685 grind

There are other cams on the market but these are the most popular.

If all your going to do is put a higher comp piston in then, then your ok with stock valve springs.