SAFETY FIRST: Protective gloves and eyewear are recommended at this point.
It is possible to rebuild nearly every starter motor in use on a motorcycle or ATV, but before you start it’s best to do a little research. Checking at your local shop, you may find that a starter motor for your machine is fairly inexpensive. If that’s the case, it is hardly worth the effort of taking apart an ailing starter motor even to diagnose what may have gone wrong. If your replacement starter motor is on the pricey side, look deeper to see what replacement parts are available. Often you can replace the brushes, but if you have a bad armature and can’t get one you’ll be replacing the whole starter anyhow. The same situation exists with the end cap bearings—many machines list new end caps unavailable as a replacement part.
The best advice we can give is to use this chapter as a diagnostic tool. If your $200 starter motor only needs a set of $35 brushes to get going again, you can save some money doing a rebuild.
All starter motors follow a similar design, with a few differences according to use and individual brands. Here we will show you how to take the motor apart and troubleshoot problems, and how to get the starter back together and serviceable again. Individual specifications, such as armature coil resistance, brush length and commutator diameter will vary from each different starter motor, so use the specifications for your particular machine as the final guide when you’re examining the motor.