How big?

[chico_2007]

I would like to know what is the highest compression i can go with a piston on my suzuki z400 without having to run it on race fuel?

[IrideMHSC]

12.5:1 i think?? Im not positive...

[PeeWee21]

Honestly...i would'nt go over 12:2:1 myself. 12:5:1 is at that edge where you risking detonation. You can run 12:5:1 with a mix of premium gas and race fuel.