Make sure that if you install a new coil to properly gap it between the coil and the flywheel. A real sloppy, but effective way to do this is to get a nice, new business card, loosen the coil bolts, slide the business card between the flywheel and coil, rotate the flywheel until the magnets on the flywheel sticks to the coil. The business card will be sandwiched between the flywheel and coil. Tighten the bolts, slide the card out. That's your gap.