Bike started fine rode about 20 miles of 2-tracks and the engine was running at a very fast idle. It wouldn't stall in 1st gear with the throttle closed. I disconnected the throttle cables. No change. I removed the hot start (Dr.D) and inspected. Appeared to be functioning. Still fast idle. When I got home I installed the factory hot start. Now it won't start. I assume that it is lean but what is causing it?