I just completed a full engine transmission swap on my bike. Everything works excellently now, I even have a second gear (the reason for the powerplant swap) I simply un-plugged the motor with the defective gearbox and stuck in a whole new motor, complete, untouched from the donor...So I now have a different stator and a different starter motor as well as the internal wires that stay with a complete motor. But I still have the very same behavior from this new motor's starting systems....

I still have my intermittent 'no start' issue. Sometimes (maybe 50% of my rides) after about 50-100 sporty miles the bike has a 'dead battery' when I try to start it after a brief stop.
The lights come on, looks normal and everything but when I touch the starter switch....everything blanks out, sometimes after a couple of half-hearted rotations of the motor..sometimes just a 'click'. I can push start it then and ride for a mile or two....then it cranks and starts right up again with the button.

I rode home this evening, about 10 miles, after a 'no start' episode and tested the battery voltage...it was at 12.77v, about 80%... When I test the voltage output at the battery, I see good charging. This is exactly the same symptoms I saw with my old motor...I now have a different stator, starter, and I think maybe the switches too...I forget... Just doesn't make sense to me..anybody want to guess?

I did clean the terminals of the battery as I installed the motor and I used the main switch/relay/fuse bundle from the new motor....I looked at the wires as I had things out and couldn't see any heat issues. The bike was 'kid-owned' and not well maintained when I got it....
Now that the motor and tranny are working so well, I can start to try to trace this glitch down...anyone have any hints on where I should start? Could it be as simple as a crap battery?....When I leave it for a week on the battery tender it reads about 12.8v after I turn the lights on for a few minutes and let it stabilize again...
Thanks in advance if anyone has any ideas.

Don Hanson

 

I'd start with your starter solenoid. The connections get corroded and can cause non start issues.