I have a 1983 XL600R. I have replaced the cam / rockers / and a new head cover gasket seal, oil pump, oil lines, and completley rebuilt the carb with new seals and float valves. I assembeled the engine, and finished adjusting the valve clearances. Then I turned on the fuel (kicked it over a couple of times to get fuel in the carb/engine. I turned the ignition on and on the 1st kick and WHAM - It instantly started on the first kick. It was idling perfectly, and I reved the engine vroom, vroom, everything sounded great. Then after about 2 minutes I turned the bike off. Now I cant get it started again. I have tried everything... Any Ideas? I have check the spark and it's good (new plug too). I have kicked it over about 20 times with the fuel off to insure it's not flooded? tried it with the choke on and off....and it wont fire up? Any ideas? Since it started and ran for about 2 minutes (before I turned it of) I assume that the bike has most of the adjustments within the proper specs? I have double checked everything and I'm not sure what to do now?