I have a 1998 Formula 583 DLX that blows the headlight bulb when I rev it up to around 4000 rpm. This is the only bulb that blows. Happens to both the high and low beam. All other instruments and instrument bulbs are OK and work properly. The problem began when I replaced the voltage regulator to repair the problems I had with the electric start. The electric start works perfectly now. I redid the ground on the regulator and the main ground from the battery to make sure they are good but still have the problem. Hope someone can help me out here.