Xr head gasket & compression question

[d90rick]

Hi guys. I was reading the articles section on here with mickey dunlap. He mentioned that with certain pistons you dont really get an increase in compression since the pin to deck height is the same in many cases. My question is, has anyone simply done what he talked about with using an xr400 headgasket & using just silicine at the base of the cylinder to increase compression? If so how did it go & how much of an increade do you get?

[ish416]

All of the aftermarket piston manufacter's that I am aware of: Wiseco, JE, and Namura all base their compression ratios off of the XR400 engines (gaskets). The EX gasket was thicker resulting in a .2 - .3 drop in compression. So your 11:1 Wiseco or JE piston would actually be 10.7 - 10.8:1 with the EX gasket and become a true 11:1 with the XR gaskets.

I have always ran XR gaskets with no base gasket. It should give you whatever compression ratio is advertised.

[d90rick]

I wonder if it would make much of a difference if i did the xr & silicone on my stock bore & piston. Right now i hv aluminum airbox w/ a uni,sparks pipe & timing key, jetted appropriately w/the needle at thr 3rd position. The motor runs tight so i was looking for a simple gain. I dont really want to change out piston etc until it needs changed, know what i mean?