Im trying to pick a piston for my warrior, I want more than 10.25/1 but I want to be able to run on premium pump gas. How high can I go? I know it will make it run hotter and im dealing with that at the same time as adding more power.

 

Depends on riding style and mods. For automobiles, 10.5:1 is max for pump gas. If you have air conditioning, stay under 10:1. See what I mean by riding style? If you lug the engine at idle, such as when the air conditioning is on, you want lower compression to reduce heat. ATV engines are a little more forgiving though. You could get by with 11.0 with the right mods. If it has a GOOD port job, it can stand higher compression than if it is poorly done. Your cam size will very the amount of compression you can run due to valve overlap that huge cams experience. I think you should just stay with the 10.25:1 piston, then you shouldn't have to worry.