Diagnsing charging system

[Jr.]

I am new to this site hopefully I can find some good information here.   My Motorcycle will not charge the Battery Voltage at the Batt cables does not change when revved up.
 
I have fixed up a 1978 CB750K8 SOHC, I am using a clymers manual  I have tested the rectifier the 6 diodes are good according to what I have learned about testing it. I have been told that the voltage regulator is mechanical and there really is not a way to test it but I have adjusted it according to the manual.  The field coil tests at 8.2 Ohms no short to ground, the manual says it should be at 7.2 does that make it bad, some have said no. The stator tested around .555 Ohms and no short to ground. I have not been able to test the rotor slip rings because that part is still on the bike I will be taking it off tomorrow to test the rings i have researched what it should test at and from what I have found it should be between 4.2- 5.0 no higher. Are there brushes to this assembly and should there have been oil in the Left side cover where all of this is? I have been told yes there should be. The battery is fully charged.  Can anyone confirm or correct any of this? If you can add  anything to my knowledge or if anything that I have learned is incorrect I would be happy to learn from you. The bike is ready to ride besides this. Thank You.

[TOOLS1]

Forget about testing the rotor, and rings, as that is the DOHC charging system. The most common charging problem on the SOHC is the stator wires coming unplugged behind the engine side cover. I would pull the stator cover, and check them before doing anything else.
TOOLS

[Jr.]

Thank you tools but I have done that too, that is why I asked if there should be oil in the cover when I took it off oil came out. so there is no point test the rotor then or is there even a way?

[TOOLS1]

On a SOHC there should not be any oil in the stator. The rotor on a SOHC is just a chunk of iron that spins inside the stator. And neither of these hardly ever go bad. However the stator can be tested without removing it from the bike, just follow the instructions in the factory service manual. If you do not have one, you can download it for free from the manuals thread at the top of the home page here. Also the wire connections I was referring to are behind the shift cover.
TOOLS

[Jr.]

Now I know that I have an oil leak in there some where  and I will look into seeing how to test using one of your factory manuals. I'm sorry I was not clear I have removed both covers and have exposed  those wires and tested the stator and field coil that way too and got the same results I previously stated.  But I willl see how one of your factory manuals says to do it. So where would the oil leak be coming from then? I need to get this on the road asap. Thanks

[Jr.]

I have been read the honda service manual for my bike and I have not found the resistance that is allowed for anything just to check for continuity also what would make my rectifier wires get hot? I did however figure out how to test the voltage regulator.

[icerigger]

You could also try this. Probably the definitive diagnostic for charging systems.

http://www.motorcycleproject.com/motorcycle/text/SOHCcharging.html

http://www.motorcycleproject.com/motorcycle/text/SOHC_chargeFAQ.html

[Jr.]

Thanks this will help.  Is the only place the oil would be leaking from inside the stator case the crank seal behind the rotor and fly wheel?

[TOOLS1]

Jr. wrote

Thanks this will help.  Is the only place the oil would be leaking from inside the stator case the crank seal behind the rotor and fly wheel?

Yes. If memory serves me, you should be able to replace that seal without separating the cases.
TOOLS

[Jr.]

I have a 1978 CB750K8 and it is not charging.  I have been doing bench tests.

The field coil should be 7.2 Ohms and it tests at 6.8-7.0 it fluctuates and short to ground

The Stator Coil should be 0.2 Ohms between the 3 wires I am calling y1 y2 y3 and it tests at No short to ground either.

 00.5-00.4 between y1 and y2

00.5-1.0 between y1 and y3

00.4-00.6 between y2 and y3

The Rectifier tests fine with the diodes tests both ways

I have found many ways to test the voltage regulator and do not know which to trust.

Can anyone tell me if the field coil and stator are within range or are out of it. They are close but I do not know if they are close enough??