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Discussion Starter · #21 ·
Here was my concern. Several of us including myself have advised that the three yellow stator wires should produce 90 plus volts ac in any combination, at elevated rpm. That my Deluxe was only producing 30ish vac was seen by me as the cause of failure to charge the battery. All static tests of the charging system were good. I proceeded to order parts and disassemble the engine. Then I watched a couple of stator testing YouTube videos that said 30ish volts was okay. Got me to wondering if the 90 vac advice was incorrect? Today I tested the 3 yellow wires on the temporary replaced Deluxe motor, it was near 100 vac. Case closed as far as I’m concerned, 30ish vac will not charge the battery, that is too low and the problem will be with the stator, even if failure cause cannot be determined. I think the YouTube video was a Partzilla production too, covering various mc charging systems.
 

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'84 CX650E that is evolving into a GL500
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At one time Rob Davis had pictures of a stator tester on his site that he made from a biscuit tin and 3 lamp bases with household incandescent light bulbs (240V but I can't remember the wattage). With it hooked up to the 3 yellow wires and the engine running he expected to see all 3 bulbs brightly lit if the stator was working properly.

I don't expect 30V would make a 240V bulb light very brightly but 90V would.
 

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Discussion Starter · #23 ·
Agreed. Not finding a test fault and then seeing the YouTube tutorial proclaim 30ish vac as good had me second guessing myself. The stars are back in alignment again, I’m ok with not knowing the exact type of fault, just that it is failed. The growler test apparently charges each phase vac making the individual coils electromagnets, which are then tested for magnetism strength with a steel band looking for weaker coils. Basic but clever nonetheless.
 

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Another possibility just occurred to me: If one or more of the magnets lost strength the output voltages of all of the phases would decrease equally. I seem to vaguely recall something about a stator with weak magnets at some time in the distant past; It certainly isn't a common issue but it might be worth checking while it is apart.
Unfortunately magnetometers aren't very common, not to mention that the specs for things like that were never published. The only test I can think of would be comparing how strongly it pulls on something made of steel with a known good stator (to decrease the voltage that much I'd expect a significant decrease).
 

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Discussion Starter · #25 ·
I considered that, and held a screwdriver to each magnet to do a very rough evaluation of the magnet’s pull. They all seemed to be about the same and compared favorably with another rotor I had on the bench.
 

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Here's an uneducated and not necessarily correct guess.

The wires have corrosion which would increase resistance and decrease output.

They also have failed insulation allowing the coil to bypass much of itself returning resistance more or less to normal.

Two faults, low charge rate. Passes testing.

Unlikely, but a possible explanation.
 
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