Don't run you rmotor a wot(wide open throttle) for more than a few seconds, or mile or so. Put a dab of grease between the two gears on the right hand side of the motor. Grease the chain when it looks dry, or every year or so. Make sure your chain tensioner is not so close to the back sprocket that is causing the chain to bind on the sprocket. About 1/16" play is good. About your pedal hitting the crank, you can get a wider crank on any of the sights to either side of the forum.