Hey guys this is my second top end rebuild but this time I've been having trouble with my bike not starting after I did a top end. When I try to start it all that happens is a backfire after every ten kicks or so. I have a brand new cylinder,new timing chain,new valve springs, and I had the valve seats re cut by a reputable machine shop. I have stage 1 hot cams that I installed on my last rebuild with no issues. I re shimmed the valves and i'm within tolerance according to the manual. I'm pretty sure I have the timing right and I know i'm at tdc. I'm going to check the carb again tomorrow, but did I miss something? could this be an ignition issue? http://www.thumpertalk.com/topic/569169-yz450f-07-wont-start-after-top-end-rebuilt-please-help/ did some searches but no luck for me.