I was reading Broggy's Winter Work 2016-2017 thread where he was working at getting the starter brushes back in and remembered that I had taken some pictures to show how to get the brush holder and brushes assembled to the armature. The opportunity to get the pictures came about when the wife's bike stranded her at a gas station. The brushes in the starter were completely frozen in their holders and unable to move out and make contact with the armature. Click click, no go. Normally I forget to take pictures but this time I made sure I took a couple. Here is how I brought her dead starter back to life. This is what it looked like when I opened it up. 2014 XR 10 k miles.
After disassembling it I gently removed all the rust off the armature iron with emery cloth, very lightly sanded the commutator, then cleaned the grooves out on the commutator with a hacksaw blade that has been ground on the sides to reduce it's width to that of the grooves and also removing the set from the teeth of the blade so that it no longer cut on the sides. I didn't want to widen the grooves while cleaning them. This starter is almost new so there was no need to undercut the insulator between the segments, just get the crud out and remove any conductive residue from between the segments.
When it was clean I ever so gently deburred the edges of the commutator segments so that the brushes wouldn't lift on any burrs that I created while cleaning between the segments and cause arcing.
These next pictures show how to get the brushes to stay in place while you assemble it and the clips I make from baling wire to hold the brushes in place.
Also this starter had one brush that had experienced a lot of arcing. Looking at it's contact face it looked sponge like instead of smooth. It needed to be ground down till good brush material was present. This picture is of the simple tool made from a socket slightly smaller than the commutator that was used to do this. Once made you place it in the brush holder, release the brushes and let them center the tool. Then rotate it by hand in the direction that tightens the sandpaper on the socket checking occasionally to see if the offending brushes have cleaned up yet or not. It doesn't take long to remove the burnt and of a brush as it has no real strength. You need about 85-95% good contact surface.
Doesn't look like much of a tool but it works.
When making the tool you measure the commutator diameter with calipers then wrap the socket with wet and dry sand paper till you match that diameter. You should try very hard to end up at the same size as the commutator because the radius of the contact surface of the brush must closely match the radius of the commutator as close as possible. Four of those little segments must transfer almost 300 amps without arcing excessively when you push the start button and they aren't any larger than they absolutely have to be to get the job done. If the radius's are off it greatly affects the amount of contact area and you risk pulling copper off the armature commutator segments and welding it to the brushes which really screws things up.
So just take your time and measure the diameter carefully.
Put it back together and it works good. Push the button and it fires right up.
Unfortunately I couldn't find any reason why my wife's starter had gotten so much moisture in it?
I'm not sure why some Vic's have moisture problems with the starter and some don't?
I did wipe all the orings down on reassembly with silicone gasket sealer in the hopes that perhaps one wasn't sealing completely and gasket maker would help. i couldn't find anywhere that a oring was cut etc. though.
I would have much rather had my wife's starter looked like Broggy's inside which was rust free, but those are the breaks.