Thread: 1980 Ct70

Question, What is the most likely cause for a 3 speed auto that will not stay in gear? I received this bike with the right crankcase cover off and a few pieces missing.
Question? I have a '72 engine in good working order and was going to swap. The wiring coming out of the motors are not the same. Would it be best to swap the rectifier and flywheel?

Well, depending on what those few missing pieces are, it could be that.

Often times, it is the clutch that is causing the problem and it just disguises itself as a tranny problem. You could have a worn pressure plate, discs or springs or all three.

If you are having trouble actually shifting, it is probably worn shift forks. But if it shifts okay but just doesn't stay in gear, I'd start with the clutch.

As for your engine question, the 1972 didn't have turn signals, so there is no lighting coil and hence the different wiring. If you want turn signals, you will need to see if your 1980 stator plate and flywheel will fit your 1972. Then you will have the extra wire coming out of stator for the lights. As for the rectifier, no change is needed. They are both 6 volt.

Originally Posted by ckyle29

.....As for your engine question, the 1972 didn't have turn signals, so there is no lighting coil and hence the different wiring. If you want turn signals, you will need to see if your 1980 stator plate and flywheel will fit your 1972. Then you will have the extra wire coming out of stator for the lights. As for the rectifier, no change is needed. They are both 6 volt.

The `72 does have a lighting coil but there are only 3 wires that come of the stator assembly. Black off the ignition coil and Green and Yellow off the lighting coil for the headlight, taillight and horn.

Just FYI

Ian

They all have a lighting coil. What do you think runs the headlight?

Thanks for the reply. Missing parts included an O ring, through oil & spring which I replaced. When I got the bike it had this problem and the right side crankcase was off. I reassembled with new parts, got it running. I seems to shift ok, it has a good feel but won't stay in gear. I don't have any expierence with the auto trans so any help would be appreciated.