I have been chaseing a problem for 2 months now. the motor misfires at idle and low rpm. thought it was fuel related so I clean carb and jets and replace intake gaskets and carb gasket. sometimes it runs o.k. and sometimes it just doesn't seam to have any power. the exhaust has a different sound to it. well anyway, I check compression 150 in each jugs. sparkplugs looks o.k. a grayish color. I thought about the coil being bad, but I have never had a coil go bad, and I have wasted alot of money on coils though the years. the bike is a 1990 fltc with a 80 evo motor. I guess my question is how likely is it to be a bad coil? are hd coils known to go bad. any other suggestion would be appreated.