Originally Posted by NerpAngel
So tonight i finished setting up my bike with everything and I was excited to test her out. I mixed my fuel and oil and poured some into the gas tank and screwed the cap back on. I mounted my bike, opened the fuel valve, pushed the little pump button on the carb once just for kicks and giggles, pulled in the clutch lever, and off i went. I started pedaling and everything was going smooth so I decided it was time to test it out! I let go of the clutch lever and boom it started to sing for a second then slowly died on me.... when i sat there confused as **** i looked around and saw my chain had completely come off the rear sprocket.... lol? I'm assuming the engine died in about 2-3 seconds because the chain came off the sprocket and wasn't pulling anymore. I got my chain back on and re adjusted the "chain tension" piece of crap that came with the kit and tried it again only to have the chain come off 1 or 2 seconds after i released the clutch lever..... So... any help? plEASE?!?! I WANT TO RIDE SO BADLY~!!@
The chain tension and alignment is very important. Let's start at the rear sprocket. It must run true with no wobbles. Is the sprocket perfectly centered on the hub? Check it for lateral alignment as well as vertical.
Chain tension: You'll want about 1/2 to 3/4" slack in the upper portion of the chain when the lower is tight. You'll also need to assure that the tensioner wheel is aligned with the chain and not pulling it to one side or the other. Every kit supplied tensioner bracket I've seen requires a slight twist to get the centerline of the wheel to align with the path of the chain. You can clamp the bracket is a vice and use a large adjustable wrench, Channel Locks, Vice Grips, whatever to twist the bracket so the wheel is perfectly lined up with the chain. Heating the bracket is not necessary, it will bend/twist cold. Start there and get back to us with your progress.
As a side note you're going to hear from those who preach to get rid of the chain tensioner. That is bad advice. Unless the chain alignment and tension is absolutely perfect you run the risk of the chain derailing at speed due to chain sway and the lack of anything to help guide the chain onto the rear sprocket. There are many optional methods and improvements to the kit tensioner but if installed correctly and carefully, they will serve you well. One important piece of advice is to secure the bracket to the bike frame by some method that will prevent it from loosening and rotating into your rear wheel/spokes. That can be a dangerous and expensive event you'll want to avoid.