Motorcycle Repair: Battery not charging, stator windings, regulator rectifier

Question
My son has a 1980 Honda 750 that went down when he hit a deer.  The case over the generator got cracked. Since then it doesn't seem to be charging the battery.  We replaced the brushes module (one brush was broken) but once the battery runs down the bike not only doesn't start but once jumpped will only run for a minute and then dies.  How can we trouble shoot where the problem is?

Answer
Bill, check the field and stator windings.  They should have equal resistance between the windings on the stator and no continuity to ground.  The field coil should also not have any continuity to ground. If those check out, the problem is most likely in the voltage regulator/ rectifier.

Regards
Rich