I've owned and raced my TC510 since it was new. It was always reliable and would start in a couple of kicks, even when hot. Last fall I started having trouble getting it started, and eventually it wouldn't start at all. Over the winter my Husky mechanic couldn't get it started, he cleaned the carb and it started right up. I trailered it down to Georgia from Canada this March and when there I couldn't get it started. After maybe 30 kicks, it would start. It would occasionally backfire when kicking it. Sometimes it would start in 2 kicks, but mostly it would take 30 plus kicks. If it were warm forget about getting it started. When started it would run strong until I shut it down. When I returned home, I brought it back to the mechanic. I talked to him today and he said the bike starts every kick, whether it's warm or cold. He can't figure it out; he checked the valves, jetting, and carb, and everything is good. What could be causing this intermittent problem, a once reliable bike is becoming a real headache.