Not sure what year, but it will start right up, run for about a minute and die out. I have pulled the carb twice and cleaned it out, replaced the intake boot, replaced air filter, and replaced spark plug. Also checked the belt switch and reset it. Getting good spark the whole way through as verified with an inline spark tester. Almost seems as thought the bowl is emptying out and not filling fast enough to keep it running, but then also it seems as though it runs long enough that if the problem was flow, it would have shut down quicker. Kind of at a loss here.

 

Does the bike run good while its running. (Rev up ok, idol ok etc..) if not then I would check the valve clearances to see if they could be a bit off. Also have you checked for vacuums leaks ?