The best place to start is with the points(they are under the flywheel).also make sure the gap between the coil and flywheel is correct(the easiest way I know is to loosen coil,get a time card or something like itand turn the flywheel until the magnets pull the coil to the flywheel and retighten the coil).Also check your keyways in flywheel and crankshaft-they have a habit of wearing and that will mess it up also(had two that did that).point gap should be about 15 thousandths.
Bob R, April 2007