have a 1989 yamaha blaster thats bored .2 over with a weisco piston, boyeson power reeds, stock expansion chamber, aftermarket pipe dont know the brand sticker was burnt, oil injection, aftermarket airfilter no airboxlid, currently running a 250 mainjet, needle clip is set on third in the middle of the needle the carb is clean fresh plug. This is the second time id ride my blaster go back to ride it a few hours later it wont start it runs hard when it wants to start no bog or backfires. any ideas to what my problem could be id appreciate any advice thank you