Topic: CB750F Testing the stator yellow leads.

[rocks]

1975 CB750F SupperSport. All original parts.

I was having a battery overcharge issues. I adjusted the regulator, now sometimes it reads around 14.6 sometimes over 15 at 3000 rpm.

I followed a tutorial on how to check the three yellow wires coming out the engine, and here how it went:

My multimeter has a 20m , 200k , 20k , 2000 , 200  (OHM)

I set it to 200, and checked between the three yellows. The number were were changing, and they were around 100 going up.

Are the readings suppose to be static numbers?
What number am I suppose to get?
Did I mess up somewhere or the stator is bad?

[bryanj]

All the wires need to be disconnected and check the meter by touching the probes together first. If the meter is a digital and the internal battery is tired you will get fluctuating readings

[rocks]

Engine is cold. I disconnect the wires emerging from the stator.  The meter is new.

Is 200 the lowest range on this meter?

When I turn on the meter, and set it 200 OHM it read 1. When I touch the probes it reads 25++.  It keeps counting up..

[Jerry Rxman Griffin aka MuthaF'er]

Most of us generally check the resistance (ohms) without the engine running. Off my head I don't remember the number you are shooting for?? Maybe 7.0 - 7.2 ohms?? BUT dfon't quote me on that. It shouldn't be the stator coils that cause it to over charge. If it's going to 15V then that part of your system (field coil and stator coil) works. Maybe someone will loan you another voltage regulator to try. That's what tells the field coil and stator how much work to do.

Checking the yellows with the engine running hasn't hopefully fried your meter. You should be able to get an AC current reading with it running but that would really serve no purpose provided the restistance readings while the engine is off are fine.

[rocks]

Just bought a new multimeter. Here are the results in this video.
Is it normal that those number change or something went bad?

https://www.youtube.com/watch?v=ofE6qwk1wzA&feature=youtu.be

[TwoTired]

What you have done so far has shown good readings.  You still need to check for continuity from any Yellow to the engine case.

If you wish to see the numbers stabilize, you have to clean the probe connection points, apply firm constant contact, with absolutely no human handshake.  Probe connection points have their own non-zero resistance contribution.

Even then, we need to see the meter specifications, to see what kind of digital rounding errors are possible inside the meter.
For example, it your meter scale is 200 ohms and the meter has a 1% accuracy (2 ohms).  Measuring .35 ohm is outside the meter's accuracy range.  Measuring resistance this low and accurately usually requires specialized equipment.

However, you almost have enough relevant information about the stator now to look elsewhere for a problem.  (Which most likely is you mucking with the adjustment screw on the regulator).

[dave500]

keep your skin off the probes aswell.

[iron_worker]

What may have happened is the the voltage reference wire (senses what the system voltage is at) may have poor connections somewhere along the way to the regulator. This will cause the regulator to "sense" a lower system voltage than the true voltage and thus it will try to compensate by keeping the field coil powered on an continually trying to raise the system voltage.

IW