what piston

[mark450r04]

I have a 04 450r and I was wondering the best piston for the stock bore, I trail ride and race occasionally and I don't want to run straight race gas.

[leadfoot_52]

Wiseco or JE 11.5:1. this will run on premium, but wont be too much to harm your rod bearings.

[nowukno]

I love my JE 13:1 thermal coated piston , it gives awesome power gains everywhere. I don't run straight race gas but i do run a mix 50/50 of 93 & 110 octane.

[DirtDevilBT]

12:1, find someone that sell one and get the stock bore one.
Do you already have a cam? Otherwise that's what I'd do first.