I just rebuilt the top end of my 2000 blaster. I did not have it bored, but I did hone it. I had the cylinder measured and I was still able to use stock piston/ring size. My problem is this. I ran about half a tank of gas through it since the rebuild and it just doesn't seem to have the power it had before. I can't understand this. The old piston was scared and the rings were worn pretty bad. It had over 160 PSI of compression and I'm running 92 octane with klotz super techniplate at 32:1. I also have an NGK B7ES plug in it. I tried a cooler NGK B8ES plug and it made no difference at all. It's not knocking, pinging or making any odd noises at all. I have a UNI filter with the airbox lid "ON" and stock carb/jetting. I'm running the stock pipe with a Bills silencer. I do have a Motion Pro twist throttle, but I made sure it was opening and closing the slide completely in the carb. Wow... I think that's everything. If someone could help me I would really appreciate it. Thanks!

 

i would check the intake and extake for the carb..

 

rebuilt motors will always be "slower" during break in period. The rings are not seated already and the machine should feel stronger after every new tank of gas....