Bad Commutators on 3 Starters

So majority of the time I've had my KZ750 I've had to roll-start it because I keep on getting starters with bad commutators. Even when they're rebuilt the brushes last maybe a month before the commutators just shred them. The only thing I've found online is throwing them on a lathe to clean them up, and while I plan on getting one eventually this one project isn't quite enough to make me get one now. Has anyone here run into this issue and a solution for it? Kind of tired of running through starters and rebuild kits/having to always make sure I park somewhere I have room to roll-start.

The issue isn't the indent left from the brushes, that's easy to sand out. Issue is the overall hump across each contact and how to make it even across the entire circumference. 
 
 

10 minutes on the lathe is the only way to re-shape your commutator.

That comutator is aweful! I don't mean to be rude but I have never seen one quite so bad!

Get the armature onto a lathe and 'true up' the comutator until the surface is perfectly cylindrical - no humps or bumps.

The surface finish should be nice and smooth also. 

Then, take a piece of hack-saw blade and carefully clear out the gaps between the segments. (remove all residual copper and carbon)

Add a new set of brushes and it will be good to go.

 

Guess it's time to see if any friends have a lathe. That one in the bottom pic is particularly bad. I have a third that was slightly better than the two pictured so I attempted another rebuild and just testing it I can already tell the brushes are getting chewed up. 

If you don't have any friends with a lathe you may check in your area for a generator/starter repair shop.  Not many around these days, but there are still a few out there.  My last thought would be to stop in at a technical school that has shop classes.  They might be able to dress up your armature for you, plus give their students some practical experience.  I must say that I have never seen any quite as out of round as yours though.

Rick H. 

Are the bushings wiped out?