2007-2009 Honda TRX300EX TRX300X service manual, Page 329Get this manual
ELECTRIC STARTER Do not use emery or sand paper on (he commutator
Check the commutator bars of the armature for discoloration COMMUTATOR BARS
Check for continuity between pairs of commutator barsThere should be continuity
CONTINUITY:
Check for continuity between each commutator bar and the armature shaftThere should be no continuity