Electric start problem

[Grmpy]

Hey guys need some help, this is on my 84 trx 200. I believe it's the exact same motor and everything as the shaft drive big red. I just got the bike, electric start didn't work, followed the wires and it was disconnected. Tested and starter solenoid is no good. Tested direct to start with jumper cable to test and the starter spins but does not crank engine. I pulled the starter and the gear in the (crank case?) Spins freely with my finger. Any suggestions would be appreciated, if it's a pain in the ass to fix or expensive I'm not going to bother. Pull start works fine but if it's an easy fix I'd love to see it working as I bought this quad for my girlfriend. Thanks in advance for any info!

[Atc 123]

If you hear the starter but its not cranking the engine most likely its the starter brushes not an exspensive fix my was like 35ish came wish the brushes and the holder take the starter off the end of it is connected to a gear which spins the motor if the gear is ok open the starter and look at the brushes just went through this on my sx