Another voltage regulator thread full of questions.

[Norton7d]

1976, on points.
In an effort to determine I am not overcharging, how does one test the brown power wire going into the VR, or the green wire coming out with the engine running?
Wont the motor die if I open up the nearest connector?
Or do I check further away from the unit at where wires end?
I did check and my VR case / shell is grounded, which I also read could be a concern.

Thank you.

 

[Jim]

how does one test the brown power wire going into the VR,

Disconnect it. You're not worried about the engine running for these tests... disconnect the reg and put a meter on it. With the key on it should read batt voltage. If it's more than about .3 (point three) volts lower than batt V, it could cause overcharging.

or the green wire coming out

Measure it at the brush.

did check and my VR case / shell is grounded, which I also read could be a concern.

Nope. Supposed to be grounded.
Finally, run the engine at about 3000rpm and measure batt voltage. Anything over about 14.5V is overcharging

 

[Norton7d]

Ok, so if i test the battery at 3k, and the hot post reads greater than 14.5, things are wrong.
Can that test produce poor results and also have the brown wire volts be ok?
Or, if two high / above 14.5, it must be due to low brown wire voltage?
Do I also measure the green wire at the brush with engine off or on, if off, does the VR even function?
Also, why does the output of the VR get measured at the brushes, arent the brushes the source for the power delivered to the VR, not the user of said power?
Lastly, is there actually a green wire at the brushes, or just wire in a braided sheath?

Thanks Jim

 

[Norton7d]

Ok, connector opened up.
12.31 at brown wire
12.61 at battery
No light on other than neutral
So it seems like I am at the edge of being in spec for that test.
Will check at brushes tomorrow with engine running.
New brushes recently installed.

 

[Jim]

Ok, so if i test the battery at 3k, and the hot post reads greater than 14.5, things are wrong. (?)

Depends on how much greater. 14.6 is higher... but I would live with that as tolerable. On the other hand 15.6 is way too much. Not an easy (and black and white) answer.

Can that test produce poor results and also have the brown wire volts be ok?

yes.

Or, if two high / above 14.5, it must be due to low brown wire voltage?

Could also be the reg itself.

Do I also measure the green wire at the brush with engine off or on, if off, does the VR even function?

engine off. VR regulates based on batt voltage. It knows nothing about engine operation.

Also, why does the output of the VR get measured at the brushes, arent the brushes the source for the power delivered to the VR, not the user of said power?

No. Brushes take power from the reg and pass it on to the rotor. Have a read here and here.

 

[Norton7d]

Charging for dummies, damn that is spot on! Will have a read once my phone charges!

 

[5twins]

It doesn't matter if the case on your type B regulator is grounded or not, it has a separate ground wire running into it. The original mechanical regulator was mounted to the side of the battery box which isn't grounded because it's rubber mounted. A separate ground wire had to be run to it. Your new automotive replacement (if it's a VR115 or equivalent) works in the same way, getting it's ground through a wire, not the case. My new one is rubber mounted to the side of the battery box in the original location, and the battery box is rubber mounted, and it's worked fine for years .....

 

[Norton7d]

Well, unfortunately I not even smart to be considered a dummy.
Here is what know so far.
My bike gets zero results on the slap test.
And with bike off, 12.6 at the battery but voltage at the outer brush is less than 6 volts, is this why I fail the slap test?
Question, how is it that the hot battery cable powers lights, horn etc thus power leaving the battery through the cable but power also comes back to charge the battery through the same cable?

 

[5twins]

Yes, DC charging voltage on a red wire coming out of the rectifier is fed into the red wire running from the battery and fuse to the ignition switch.

 

[XSLeo]

There is a charging system troubleshooting guide up in the TECH section. The TECH button is up near top of the page. In the black bar.
This leads you to a list of Major Topics. Under each Major is a list of Minor Topics.
Scroll down to the Electrical. There you will find the link to the How To Diagnose your charging system (Curly's charging Guide)or something close.anyway. There you will find a step by step guide to figuring out why your charging system isn't.
On the years that had points ignition they used a type B regulator. With this type reg a brown wire comes from after the switch to the reg. The reg reads the voltage on this brown wire. It compares this voltage to it's preset voltage. f it reads low it sends full battery voltage out on the green wire to the brush. There it flows through the rotor, out the other brush to an engine ground as well as a harness ground.
Once the battery is fully charged, the reg stops the flow of battery power to the brush. This stops the charge. The reg maintains the battery cjharge by turning off the power flow through the rotor.
On the later bike with TCI ignition they went to a type A solid state reg/rec. This functions in a similar way. It turns the power flow on and off but it does it differently. The brown wire goes to one brush a well as the reg. The reg only reads the brown wire voltage. To turn the power on and off it controls the ground with the green wire where the type B controls the power.
Hope this helps.
Leo

 

[Norton7d]

EDIT

With key on and engine off.
I get 12+ at the battery
I get 12+ at the volt meter which comes off the brown wire in the headlight bucket.
I get 12+ at the brown wire coupler located next to the battery which goes to the VR.
I only get 6V at the positive brush
I only get 6V at the green wire leaving the VR even though 12V went into the VR.
Battery readings when running
14V @ 1500 RPM
14.5V @ 2000 RPM
15.2V @ 3000 RPM

Could I run a 12V jumper from the battery hot side to the hot brush, and if it changes the too high of rate of battery Charging, what would this prove?
Bad VR?
VR may or may not be bad but also need Jim's rewinding?

Thank you.

 

[Bushyeyed1]

I have a spare stock relay and rectifier I'll sale you if your interested PM me. I purchased this but it was the wrong one for my 1980 model.
https://www.ebay.com/itm/Yamaha-XS6...539392?hash=item3419d2b7c0:g:h8YAAOSwPGBd4ChL

 

[Norton7d]

5T or anybody, can you please help understand the following:
Approx 6V at the positive brush with everything hooked up.
If I run a 12V+ jumper to the brown wire of the VR, I get 12V+ out, which I asssume indicates nothing overly apparent is wrong with the VR?
But if i take the same out at 12V+ and plug it into the connector it normally gets plugged into, the green wire falls to approximately 6V.
Why is that?
Whatever the reason is, I assume it is directly correlated to why I overcharge.

 

[Jim]

13.9 is not overcharging.

 

[Norton7d]

Those photos with the engine off.
Battery readings when running
14V @ 1500 RPM
14.5V @ 2000 RPM
15.2V @ 3000 RPM

 

[Jim]

Gotcha. I see from your pic, you have the old style mechanical regulator. It operates by quickly... (as in vibrates) a set of contacts. These contacts send batt. voltage to the rotor when closed and a much reduced voltage (couple of volts... maybe) through a resistor when open. That's the power out to the rotor. What your meter is probably showing you is the average of those two voltages.

In the Yamaha manual, there's a procedure to adjust that regulator. Pretty simple to do and should cure what ails ya... 'scuse me.... your bike.

 

[Jim]

Thinkin' more on this....
13.9V at the batt. with the engine off is a tad high to start with. 12.5 - 12.6 would be more normal. Then I looks again at your $10 meter... hmmm.
Maybe get a second opinion on whether or not your meters tellin' the truth?

 

[Norton7d]

A better meter likely wouldnt hurt matters.
I should do it again without the battery tender hooked up, that may have had an impact?
Are you sure a 76c has an adjustable VR?

 

[Jim]

I should do it again without the battery tender hooked up, that may have had an impact?

Yes, with the tender on it you're reading the tender output, not the battery. Which brings us back to the meter. Based on what you said, your meter's prolly fine.... 13.9 sounds about right for a tender.

Are you sure a 76c has an adjustable VR?

 

[Norton7d]

OK, so mine is adjustable, didnt know that but after reading many posts, adjusting is an art to itsself.
If i get a new VR (VR110 i think is the number) do I my problems disappear? Or are problems reduced to something other than the VR?