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Discussion Starter · #1 ·
A few days ago I changed the battery for a new one, but it doesn't get charge correctly. I need to check the regulator and the 3 phase alternator. Anyone can tell me how to check them? I've got a workshop manual for other monster model, but the wires are different that mine. My regulator has got 3 yellow wires and 2 red, 2 green.
I checked the ac voltaje of the 3 yellow wires alternator at 800rpm: 1.9v, 0.8v, 1.6v.
 

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To check the whole system, hook everything up, rev the motor and watch the meter, the voltage should rise with the RPMs. If not - pull the yellow wire connectors, start the motor, and measure the voltage thru each yellow wire. The Electrix site has some good trouble shooting info.
 

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Discussion Starter · #3 ·
...measure the voltage thru each yellow wire.
I checked the ac voltaje of the 3 yellow wires alternator at 800rpm: 1.9v, 0.8v, 1.6v.
The voltaje is the same at the exit of regulator increasing rpm. but increase a beat at the alternator (3 yellow wires). Anybody know what is the voltaje at the 3 yellow wires? it's those 3 voltajes I got correct?
 

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Having just gone through this with my '99 M750, it's still fairly fresh in
my mind (cautionary note: this is from memory), so maybe I can shed
some light. As I remember, my voltage check of the 3 yellow output wires
measured around 16v, not the piddling amount you got. Are you sure
you didn't transpose a decimal point? Here's what I'd check if this were
my bike: Start the engine and measure the voltage across the battery
terminals. Any rpm above idle should get you 13-15v. If less than that,
feel the regulator. If it's too hot to hold, it's fried as the zeners inside are
shorting the current to ground. Not good. You can also check the
connectors for loose or corroded fittings. ( like any of us should be so
lucky.) Also check the 40A fuse the red wires connect to. If it's blown
(as mine was), the the regulator is indeed shorted and the fuse did its
intended job of preventing a battery short straight to ground. As for the
color coding of the wires, the 3 yellows of course come from the alternator,
the two red (or red/white) are hot output to the battery via the fuse, and
the two greens are ground. My hunch is the alternator is ok, and the
regulator is toast. The cost of OEM is around $150 (ouch!) Good luck.
 

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Discussion Starter · #5 ·
I checked the alternator voltage with the "Motorcycle Electrical Fault Finding Guide" of electrosport.com and I found that it's work wrong. It's need to work ok to give 50v or more voltage. So I need to change.
How can I know the power of my alternator, I think is 300w, but no sure. My regulator number is: SH579B-11
I found somethings on ebay but don't know the part number or how can I check if fit my monster.
 
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