Greetings. I am new here. I have a 2005 Grand Vista 250 which has developed a charging problem. Downloaded the shop manual and did the tests:
Regulator/Rectifier passes the conductivity tests for the diodes using a VOM. However, the battery is not charging. No increase in the DC voltage while revving the engine. The test for the AC alternator is somewhat confusing. Of course it is a three-phase alternator. The manual says the resistance between any of the yellow wires to any of the others should be 0.6 to 1.6 ohms. I am getting about 3.3 ohms between any/all of them. No conductivity between ground and any of the yellow wires. I am not sure this slight difference in resistance is material, HOWEVER:
When measuring the AC voltage between any of the yellow wires to others while the scooter is running, but not connected to the regulator/rectifier, then I am getting about 5 volts AC between two of them, and about 20 volts on the third. I would expect to see the same results between any of the three. So, perhaps the issue is the alternator (If that's what it's called in motorcycle-talk)
Other than the alternator itself, I am also suspecting the regulator part of the seemingly dual purpose regulator/rectifier. I am hesitant to go buy a new rectifier if the problem actually winds up being the alternator.
Any thoughts?
Thanks,
-Bill