My son bought a 1985 Suzuki RM 125 Dirtbike. It started and ran for about 2 minutes and shut off. We found out that the ground wire had slipped off. After putting it back on it slipped off again because it was too short so we extended the wire. It will not start at all now. we tried bump starting (did not work). We cleaned the carb (did not work), and it still did not work. We changed the spark plug and checked to be sure it sparked (which it did). Does anyone know of anything else we can try? Thank you