alternator brushes

could someone tell me how to check alternator brushes...pics helpful

 

Doug

It is all based on the size. I will look at the Yamaha Service Manual when I get home. I bought the brushes last year from OldBikeBarn.com and replaced mine. I think (but am not sure) that they had to be 10 mm long and one was 2 mm and one was 6 mm. It made a big difference in my 82 Maxim

 

Hummm....an alternator question and no RickComatic post yet...hummmm 8)


Yes the service length is 10mm. Below this, replace. There can also be problems with the rotor though that is rare. To check output, remove the seat ,crank the bike and check the voltage on the battery with a multimeter. Below 13.5 and there is a problem. Should be reading somewhere between 14.5 and 13.8 volts.

 

here is a link to a pic. Brushes should be measured with them out of the holder. Or if you see a line in them like the pic, then all sould be good. If close to the line go ahead and replace them.
http://www.xjbikes.com/Forums/viewtopic ... cture.html

 

I sorry ... I had to spend some time in the shop. People need their Carbs Cleaned and it really bothers them when I'm taking a break.

Pull off the cover.
Three Cap screws.
Inside the cover you'll see the brushes mounted on a little platform.
Measure how much is left from where they stick-out the holder to the end.
10-11mm is the limit.

But, look for chipping and signs of arcing on the rotor.
If you see that stuff.
Replace them.