Recently purchased a 1980 xt250 for 75 bucks at an auction. Looks like the guy was in the middle of putting on a new timing chain, tensioner and cam gear. I followed the manual and put everything together. She tries to start but I can´t get her to run on its own gas. It will run if I spray carb. cleaner through the carb. but only for a few seconds. I´ve been through the carb. (new kit). It seems to fill the fuel bowl. But no luck. Any help is appreciated.