Well, I tried that little 1/3HP motor (that came out of an old 2 wheeled scooter) as a starter motor for the 6/1.
The short story is... It didn't have enough power. sigh...
Oh well, it only cost about 2 hours of time and a bit of MIG wire to find out.
After staring at the motor for a while and thinking about where to get a hockey puck for a drive roller, it occurred to me that I didn't need no stinking puck... everything I needed was there on the scooter!
I ended up cutting the entire rear end out of the scoot and I welded a piece of pipe on the bottom for a pivot, and a piece of pipe on one side for a handle. I tacked a piece of steel round bar onto the frame of the 6/1 to slip the pivot end of the starter onto, and that was all I needed to test it.
The tire from the scooter gave good traction against the 6/1 flywheel. The tire is about 8" in diameter which gives about a 3:1 reduction to the 'roid. The little motor has an 11 tooth sprocket and the sprocket on the wheel has 55 teeth which gives 5:1 reduction, for a total of about 15:1.
With the compression release on, the motor spins up the roid just fine. But as soon as the compression release is disengaged, it will only pull through 2 compression strokes, and it stalls on the 3rd one.
If that motor had about 30% more power it would probably do just fine.
The gearing is very good. If the ratio was higher it might be able to pull through the compression strokes, but the RPM probably wouldn't be high enough to start it.
Oh well, it was an easy and cheap experiment at least. I guess I'll be keeping my eyes open for a real starter motor for it..