Just bought a 84' cr250r. Won't start after riding. Even a ten minute ride. It will push start though. It has to sit at least half hour before kick starts again. The guy I bought it from told me the bike will run better when it cools down outside. Been in the 90's here in Michigan. About 2 hours on rebuild. Changed plug from a 7 to an 8. Carb was cleaned during rebuild (keihen pwk). I'm a newbie to working on these bikes. Any thoughts!?!?