Chain Keeps Jumping Off the Motor

[Hannibelle]

This is my first electric bike build. I used a 24v Razor scooter motor and custom sprocket. The motor chain keeps jumps off, especially when on full power. There is a little bit of slack in chain by half a chain link. How can I fix this?

 

[Seabass]

Cut a link out and get a half link. Or move everything so it will be tighter.

 

[crassius]

or add a chain tensioner

 

[2door]

This is my first electric bike build. I used a 24v Razor scooter motor and custom sprocket. The motor chain keeps jumps off, especially when on full power. There is a little bit of slack in chain by half a chain link. How can I fix this?

Chain tension probably isn't the issue but sprocket alignment is. Unless the drive and driven sprockets are perfectly aligned you're going to have chain problems. A very loose chain can be a problem but alignment is usually the culprit.

Also a chain that is too tight can also give you problems. Roller chain requires some slack, usually about a half inch is good.

Tom