2005 Bombardier Rally

Hi, I'm trying to help my husband fix his atv.  It is a 2005 Bombardier Rally 200.  He says it probably has no more than 150 hours on it.  When he starts it, it grinds before starting.  Sometimes worse than other times.  He thought it would be the starter.  When he tore it apart there were black powder inside, but nothing looked bad. Dealers said to clean the bendix spring? but where is it, it's not in the starter or in any schematics I've looked at.  Any other suggestions??  

The bendix is the gear that is on the end of the starter, the bendix spring is between the starter motor and the bendix gear. If the starter isn't engaging properly you will hear a gringing noise. The bendix gear or the flywheel should show some wear if the gear isn't engaging.
He can bench test the starter and check the flywheel, be sure to turn the flywheel and inspect all of the teeth.
Most important is to check the load on the battery, connect a meter to the battery and try to start the bike while watching the voltage, below 9vdc the battery is weak.


Best of luck  
Heres my toys
YFZ450 "06" jet kit, zip tie mod, cam mod, sold
Raptor 350 "06" stock, sold
Predator 90 "06" stock, sold

the black dust sounds like brush material from the brushes inside the motor, if these are worn out and weak then the bendix wont engage properly as the voltage going to the starter will be severely decreased not allowing the bendix to go all the way out.  take the starter to your local parts store as michael suggested and have them bench test it for ya.  
Keep it RUBBER SIDE DOWN!!