I replaced the overriding clutch, put everything back together, and happily my CFMoto now starts every time (at least a dozen starts in a row without any slippage at all). Thanks again for the help!

Thanks for your advice. I pulled the magneto rotor again, didn't see any problems, i.e. the shaft was clean. I used some WD-40, put it back on, and cranked on the sleeve bolt with an air wrench, with probably a lot more torque than the 40 lbs specified, and lo and behold, the magneto seated far enough that I felt it was within tolerances. I put everything back together and it ran like a champ. Thanks again!

Here are a couple pictures. As I said in my prior post, using the puller tool it was very hard to pull the magneto rotor off. Getting it back on is very difficult. I'm probably 1/8" from where it needs to be, and the fan sleeve and bolt, using torque well in excess of recommended, won't pull it further into place.

I pulled the magneto rotor using a special puller tool (took some doing, but it came off) in order to replace the starter overrunning/overriding clutch. Now I am trying to put it all back together, and I cannot seem to get the magneto rotor to go all the way back on. The spacer behind it has perhaps 1/4" of play. I've tried using the sleeve and bolt that screws into the end of the shaft to push the magneto rotor on, with no success. Perhaps my impact wrench is too weak?

Any suggestions / special tools / techniques that anyone has used successfully?

Thank you both for the quick replies. I will go ahead and replace the overriding clutch. I'll also take a closer look at the driven gear for wear, and replace it if wear is noticeable. Even though I'd rather not spend the money, time is money, and I'd rather not open everything up again later to try to fix it again if the problem persists.

My starter sometimes starts my CF625, and sometimes it just spins without engaging. I replaced the starter, same problem. I opened up the engine where the starter gears are, and everything looks great to me. No broken teeth, everything clean, no obvious (at least to me) signs of wear, gear teeth engaging and turning as expected. The overriding clutch appears to be working just fine. It turns freely in one direction, but locks up and won't turn -- at least not by hand -- in the other direction. Yet the only thing I can think that would allow the starter to spin without engaging/cranking the engine would be a bad overriding clutch. Is it common (or even possible) for the overriding clutch to be faulty, so it sometimes doesn't lock up and allows the starter to spin? If I replace it, should I also replace the driven gear that the overriding clutch locks onto and turns, just in case there is enough wear-down on it to reduce the reliability of the overriding clutch locking on to it? Thanks in advance for any help on this!