I'm getting back into motorized bicycles after a long break. I built a 50s retro motorbike out of a 1995 Schwinn Cruser Deluxe. Bought the bike new in 1995, and added Schwinn Phatom parts at that time. Last winter I added a PK-80 motor with a Fatcat exhaust. The only thing that will change is the stock sprocket and chain tensioner. Any suggestions as what would be a good replacement?