so here's all the details i can give. i did a top end rebuild on the bike (piston and rings) - Valves were booked into the bike shop the week after, during this week i ran the bike in. (it was raining the day i was home and able to ride). Took the head back out and sent it into my local dealer and when i put it back into the bike - she was a no-go'er!- cam timing is perfect, my mechanic came round and checked it out for me, I replaced the coil, and spark plug, and still have spark. i kick the bike and i get a backfire every so often, and it shoots a hell of a flame! just wondering if anyone has had the same problem? or knows how to fix it? Cheers.