79 XS750 Stator

Garc

New Member
Sonreir said:
I'll grab a diagram and post it up early next week.

For the field coil, we can test that, too.

Field coil wires should be either brown and green or black and green, coming from the alternator. In either case, use your multimeter to read resistance between the two wires. Then read resistance between each of the wires and ground.
Post up your readings and we'll take it from there.
All tests were open except from Green-Brown Brown-Green 3.8 ohms.
 

Sonreir

Oregon
Field coil sounds good based on those tests. Did we already do these tests for the stator? Same routine. Measure between each white wire and ground and then between each white wire.
 

Garc

New Member
Sonreir said:
Field coil sounds good based on those tests. Did we already do these tests for the stator? Same routine. Measure between each white wire and ground and then between each white wire.
.7-.8ohms both ways between all whites, no continuity anywhere to ground.

Have tried red and green from the rectifier side direct to battery, still minimal AC voltage. Maybe .5VAC while running out the stator between whites disconnected from rectifier.

A 40 year old bike circuit can’t be this difficult, can it ahah?

Green to red in the R/R plug side has 1080 ohms, nothing flipped. Again, other green to regulator is grounded.
 

Sonreir

Oregon
OK. Stator sounds good.

From the R/R, where do you have the loose black, white, and green wires going?
 

Garc

New Member
Sonreir said:
OK. Stator sounds good.

From the R/R, where do you have the loose black, white, and green wires going?
I’ve tested a some different combos to the field coil plug, but green-green white-brown Black-black. The green/brown of the coil should technically be all I need to use based on the wiring diagram.

Should I hook up the loose green from the R/R direct to ground, that better be the solution to what the field coil needs as I know it has not been attempted.
 

Garc

New Member
So the loose black is the signal switch, hopefully that is literally the key to the loop otherwise a new stator is next. Shouldn’t matter unless the R/R is internally switched as I’m going direct to battery positive and negative.

I did not have magnetism with key on through cover, however it is primer, paint, and cleared.
 

Sonreir

Oregon
The black wire serves two purposes for this type of R/R:

1.) It's the power source for the R/R and so without power on this wire, you don't get any power going out on the white wire. Unlike many PM R/Rs, the red wire on this unit is output only.

2.) The secondary purpose is voltage sensing. As the electrical load on the system changes, the voltage will increase or decrease on the brown wires in your harness. The black wire (being connected to the brown) will detect the change and vary the output to the white, accordingly.
 

Sonreir

Oregon
The green wire on our unit is a pass-through to ground, so you can still hook it up directly to the unit.
 

Garc

New Member
I’m under the impression the entire unit is grounded through the battery negative green and flowing positive (charged) voltage through red after being rectified.
 

Sonreir

Oregon
Garc said:
I’m under the impression the entire unit is grounded through the battery negative green and flowing positive (charged) voltage through red after being rectified.
Yup. More or less.
 

Garc

New Member
No luck tonight with power to black R/R wire.

Mind bottling really, between whites will go from .1VAC to .5VAC with a little revving.
 

Sonreir

Oregon
OK. Next test.

Disconnect the R/R from the stator and double-check that the green wire (the one bundled with the red) is grounded and that the red wire is connected to the battery positive terminal. Verify that these are good connections by reading DC voltage between the red wire and ground (should be around 12.5V) and then measure resistance between the green wire and the battery negative terminal (should be close to zero Ohms).

Now, connect the black wire to the battery positive terminal along with the red and repeat the DC voltage test on the black wire to be sure it has power.

Finally, measure the DC voltage between the white wire and ground. We should have about 12.5V here, too.
 

Garc

New Member
Do you want the plug green chassis grounded or to negative battery?

Also, verified there was voltage through loose green and white wires to the stator last night. Going to voltage with the black wire makes every wire powered except the white ones I want and green plug negative.
 

Sonreir

Oregon
Garc said:
Do you want the plug green chassis grounded or to negative battery?

Also, verified there was voltage through loose green and white wires to the stator last night. Going to voltage with the black wire makes every wire powered except the white ones I want and green plug negative.
For the green wire, have it hooked up however you plan to have it once the bike is up and running. Either is technically fine.

How much voltage was on the green and white wires? Unless it was 12V, then we still have a problem to sort out.
 

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