Brian, It sounds like the bike is running on two cylinders. See if you have spark on all 4 cylinders. Check your coil and connections if you don't. The most likely items to fail, are the coils, the ignition triggers and the least likely is the ignition control unit. The spark is in pairs of cylinders on that bike. one coil is two cylinders and the triggers each switch two cylinders. (1&3 and 2&4). Hope this helps, Paul