I Give Up!
I'm just a slow learner. Short version of a long story. Last year I bought a turbo for my 660. got a lot of good advice from this and other forums and even some suggestions that the rhino was not a good platform to do what I wanted to do. Went through all the jetting, etc. and just couldn't make it run right and decided to go with a larger carb. It developed a lot of blow by so pulled it apart and found that one of the ring lans on the stock piston had broken half way around the piston. Decided since I had it down I would bore it to 686 specs (102 mm.), and go with a Hot Cam, etc. Couldn't find an after market piston with a low comression ratio so ended up getting a Weisco with a 9.9:1. (Stock is 9.1:1) Talked to Weisco and they said it would be ok to shave the top off about .020 and that would bring it down to about9.4"1 which they felt would be ok if I didn't run over about 7 lbs. of boost. It ran very strong for a couple of hundred miles. I have a friend with a Rzr that has a big bore kit, etc, throttle body, dual exhaust, etc. He would pull me about 1 bike length so I was pretty happy with my setup... for about 6 runs. It died in it's tracks. Pulled the plug and could see that something had hit the plug and closed the gap so I knew that was not good. On tear down, I found that the Weisco piston had also lost a ring lan and ruined the cylinder and head. I have given up on trying to out run his Rzr and am going back with everything complety stock except for the exhaust. The old saying about if you want to play, you have to pay still holds true! Like my dad used to say "There's nothing wrong with it that money won't fix".