48 chief 74" my daily rider (if sunny and i get out of bed early enough) using ngk b7hs plugs gapped at 25. i ride at sea level in city stop and go traffic, most commonly less than 35 - 40 mph. numerous hills to lug up in both second and third gear. if i'm sitting at a long light, i usually retard spark all the way.
this year i keep fouling plugs after only 20-30 miles. usually a 1 kick bike. will start religiously then suddenly not kick over at all, no inbetween hard starting. put new plugs in and it starts right up. old plugs covered in carbon.
any help appreciated.