I'm am desperate for some help here and need some advice. I have a 49cc 2 stroke bike motor attached to a 26 inch giant beach cruiser bike. Everything is hooked up ready to go but no matter what I do my chain continues to slip off the back sprocket. I bought a spring chain tensioner which helps a little but like I said no matter what I do I can't get it to stay on. I am starting a new job soon and I need it to get there and back and am worried it won't make it there. If anyone has any advice please let me know. Just to play it safe I am buying a heavy duty chain and me sprocket my old ones have been scratched up a bit trying to get it to work. Thanks guys. I will take pictures and add them in a bit.