I thought that piston was not like they advertised,because it looks so simple like the stock piston, I also bought a Niche Big bore kit for my 01 Raptor660r and I had a very nice talk with the seller about the piston,but all they did was refund me some $$,but you say that the cylinder has a 700 sleeve? Because I was thinking of getting an L.A. Sleeve for my stock cylinder, but now reading this I'm going to hold off and just buy a Wiseco piston Kit,102mm 11:1 I think it is....i got this same kit on ebay. the piston compression is stock, not 10:1 like advertised. the piston is a flat top just like stock. the good news is that this cylinder has the 700 sleeve in it making it stronger that a stock cylinder boared out to 102mm. with that said your cases are going to have to be machined for the larger od of the sleeve in the cylinder. i have been running this for about 2 years now and no problems yet.