Yamaha TX500 alternator rotor problems! HELP!

got into this new project working on a 73 yamaha tx500 and need some help from the gear head department. wanted to hear it crank over so we put power to the solenoid and it just free spun.. thought the starter was junk.. the extra box of parts had another starter in it that functioned fine so we swapped it out.. once again, just free spun.. then we realized something was going on behind the alternator rotor, as if that rear gear wasnt catching.. jiggled it.. all the sudden its turning the bike over (without plugs installed). cool. so we put the plugs in it and it stopped catching again.. the gear on the back of the rotor is like jiggling as well.. so we took the rotor off and all kinds of parts just fell out.. pins etc (picture attached).. so anyone wanna give their two pennies on what we have in front of us? obviously something is wrong with the internals of this rotor.. any help for our first task is most appreciated! thanks guys and gals!

You're on the right track. It's the starter clutch you've most likely got a problem with, and that sits behind the rotor. In the picture of the rotor, you can see the dowels that make it work, and that crack in the starter gear doesn't look good, either. I believe you can get rebuild kits, but I haven't looked myself, as I just use the kicker anyway. You'll probably need to replace the gear, regardless, but those three Allen bolts on the back of the rotor should give access to the clutch. It works on the same principle as a stud remover- spins free in one direction, locks up the other. Good luck!

right on.. tried telling my brother we should just go kicker only but hes being really a wimp about it. lol this thing is easy to kick over, but ill agree it is nice to just press a button and get it going. thanks man ill start looking around for either rebuilds or a whole assembly on ebay.