GT380 Alternator

[miked914]

Hi All,

I've searched the posts and followed what I read about testing coils and alternator on my 1974 GT380

My coils (Primary leads) are at like 4.9 ohms on all 3

I have a Nippon-Denso alternator and performed the test from the green wire coming off carbon brush housing assembly (which would be testing the slip rings--correct??) and my voltage meter is all over the place. I have an auto-ranging meter. it will not zero in on a reading.

Bike has about 10k miles on it and is in full tear down mode right now.

Any thoughts? Am I doing something wrong? Normally I'm half-way decent with electrical...


Thanks!

Mike

[Craig380]

The coils are fine at around 4.5 - 5 ohms, no worries there.

The way to test the rotor is to put a piece of card between the carbon brushes and the slip rings, so the brushes don't touch the rings. Then put one probe on one slip ring, one on the other. Your meter should show minimal resistance. If it shows no continuity, there's a short in the rotor, which means it probably needs rewinding.

You can test the stator for continuity at the loom plug under the left side panel, can't exactly remember how, though ... sorry!

[Coyote]

Yeah. You need to check ring to ring. Resistance should be 10 - 12 ohms for the ND. Around 5 ohms on the Kokusan alternator.

[miked914]

I isolated the slip rings by sliding a business card between the rings and the carbon brushes.

Put a test probe on each ring and my auto ranging meter will not settle on a value. Its all over the board with readings. Tried with a non auto ranging and same thing, bouncing values and will not settle...

Thoughts?