I raced this weekend for the first time this year. I put 6 hours of practicing on a newly plated cylinder and a new piston and rings. The bike seemed to be fine. This weekend I had problems almost every race with the bike losing power towards the end of the moto. It was so bad that I had to pull off because I was barely making jumps. I have a temp strip on the cylinder right below the head. The hottest that it read was 185f but for the most part it was around 170f. I didnt lose coolant and the plug looked great. I even went up to a 170 on the main to see if that would help and it did nothing. I made sure the exhaust valves moved freely and they did. I am running 100 octane mixed at 32:1. I am thinking that a ring is collapsing when it gets hot but the bike isnt running that hot? Also, I did notice my bike does not smoke at all. Even when cold... if you rev it it will let out a little puff but thats it. Oh... and I have used a whole can of brake clean and even tried some propane looking for an air leak and couldnt find one. There is some blow by but there was blow by after the first hour i put it in... its black up to about a 1/4inch below the 2nd ring.