traded for this bike about a month ago, got it home and tried to crank it and it felt like it had no compression, which was weird, it was hard to crank but it did crank and ran the day of trade. i did a little bit of research and was advised to check my valve clearance, when i went to check the valves the intake was very tight and my exhaust was all the way open. i put the proper shims in to give it the proper clearance for each. bike ran great after that it cranked within 10 kicks, i did the proper break in process everything was fine, i tried to crank the bike today. ( a week later) and the first 5 kicks the bike acted like it wanted to start then sounded like a backfire and the bike doesn't feel or sound like it wants to crank.