Have a 1981 GS 550L...only sporadically fires on #1 cylinder, occasionally it runs on it, but mostly not. Changed the end cap, no positive result, changed the coil as i figured it was a defective wire, no change. The plugs have been changed out. The carbs have been serviced, and seem fine, all getting fuel. Any other ideas? the #4 is NOT missing so I kinda decided it wasn´t the coil itself..