chain problems

[edward jones]

hi i had a motorized bike for a while and didnt like the frame so i built it on a new frame today but the chain keeps coming off and its not loose. but where the chain derailer goes on the frame has a curve design which slight turns the chain is there a special derailer for such a frame for example the spring ones ?

 

[Frankenstein]

I'm only going to guess the chain comes off on the larger drive chain side. If it does then it's obviously misaligned either on top severely or the chain tensioner is aligned badly causing it to jump.

If you mean the derailleur then it's just the set screws that limit the derailleur how far it can go. If it jumps into the spot between the spokes and sprocket then adjust the low end screw by tightening to prevent this, and if the hlchain falls out between the smallest sprocket and frame then adjust the high end screw. Also re adjust the cable tension so the derailleur jumps gears properly since they are still important even on a motorized bike, especially when you have motor trouble and decide to pedal home.

Good luck and wear a damn helmet.

 

[crassius]

I often measure how far it is off, then put it in the vise and bend it that much - also, hard steel spacers between clamp and frame can shift it over if just a little bit is needed