im going to be buying a wiseco 440 big bore for my 400ex there are two choices 11:1 or 12.5:1 compression pistons i am wondering if i have to run a high octane race gas in either of them and also which will give the best low-end power of the two.


Thanks

 

The 12.5:1 piston will give you the best low end torque, but you will have to run High Octane gas since quads have aluminum heads you could get away with 93 and 103 mix. With the 11:1 you could run 92-93 with octane booster and you should be ok. I'm not sure how much you ride, but with gas prices the way they are now, i would go with the 11:1 and give up some low end.

TR