My 04rt seems to have a missfire at high rpms. But it also is hard to start and starts on one cyl. I changed the plugs. No better. When it's running at 1100rpms I disconnected one stick coil then the other. Both times there was a noticeable stumble to the engine. I did the same with the secondary plugs and found that they were also firing. This missfire is much worse when the engine is cold but never completely goes away in fact at 70 mph if I open it up. The bike Acctually slows down. Any one know what this might be?