Charging prob!! Stator or Voltage Regulator??

[donshaw]

I charged my batt and started it and the meter read 12.5. Then I took it for a ride (15 min) came back and tested it (on the terminals) it read 11.75????

Batt is good. How can I test the stator and volt reg??

Thx

[07Bolt]

put the test leads to the battey (+) & (-). Volts DC. With the bike running, it should read at least 13 volts.

Rev up the engine, it should read at least 14-14.5 volts.

If not, the regulator is unplugged or bad.

Behind the sprocket cover, is a lot of plugs. Find the fairly big one with only 3 pins in it.

With the engine running, you should not have more than .3 ohms resistance from each pin. If u do, then it might be grounded out. Therefore not charging the battery when riding.

[hdstn]

I just went through the same issue...
link (http://www.buellxb.com/Buell-XB-Forum/Buell-Lightning-XB12S-XB12Ss-CityX-XB12Scg/Voltage-regulator)

[donshaw]

The biggest plug behind the sprocket cover on my bike only has 2 pins???

[hdstn]

Thats the 77 plug where the pins short and was the issue with mine. Wasn't shorted but not making not good contact and not charging because of it.

[donshaw]

How can I test th voltage Reg??

And if it is a voltage Reg where is the best place to get one?

Thx

[hdstn]

I haven't found that answer myself. If you test everything else and all check out there really isn't much else. Check out the banner above:D

[donshaw]

I've also read that I should replace the 77 plug??

Anybody ever heard of that?

[jimijeans]

There used to be a Kit not sure check with the Dealer. Hope they are Buell Friendly.AND yes you should replace the plug. May have to buy the up grade regulator. I do remember most repairs that I do are change out to the new regulator,with the extra part included,which comes ready. You Test all the other areas which will leave only one conclusion.Test the Stator 1st with bike not running for a contunity OR ohms test.2nd, Do the Stator AC current test. BUT unplug the Regulator first for both these Tests. This test is with the bike running at 2000RPMs with 40 to 55 volts max output. Once you test these parts AND check Grounds the Terminals etc.. You will know more of what is going on w/ your bike.`Jimi

[gunter]

I've also read that I should replace the 77 plug??

Anybody ever heard of that?

I wrote a short how to for UKBEG some time ago, I think it is accessible for non-members too:

http://www.ukbeg.com/forum/viewtopic.php?f=17&t=423

Replacing the plug is done in less than 15 minutes. While you have the sprocket cover removed, also check stator for broken wires or shorts.

[mik]

I've been having some charging issues with my xb12stt. My battery voltage is 12.8V, but at idle and RPM's below 4k I only get 12.4V. I unplugged the '77' plug and tested voltage on the VR side and got 14 something volts. Plugged it back in and tested and got 12.4V at battery terminals. Battery is new (like a few months old). I found no corrosion at the 77 plug or melted/overheated terminals.

What is there between the 77 plug and the battery that could be a drain or loss of voltage/amperage?

[Theycallmecrash]

The problem with how you tested the regulator is without battery voltage to the regulator, it cant actually regulate. So you may measure 14v and change but doesnt mean your VR is working. Check engine light? Test the stator (see manual) if thats good and battery reads that low then suspect the VR cant accurately determine system voltage and has a poor output.

[mik]

"The problem with how you tested the regulator is without battery voltage to the regulator, it cant actually regulate. So you may measure 14v and change but doesnt mean your VR is working. Check engine light? Test the stator (see manual) if thats good and battery reads that low then suspect the VR cant accurately determine system voltage and has a poor output."

Good point, I hadn't thought of that. I guess I was just wanting to see what the max output of the VR would be.

Went through the whole test procedure for the stator per the FSM.

Found continuity to ground through each of the three stator sockets. Got 2.5 ohms from each stator socket to ground.
Measured 0.9ohms between each of the three stator sockets. Supposed to be 0.1-0.3 ohms.

I tested my running VAC and got
12-15 VAC at idle depending on the pin, and 22-28VAC at 2k rpms.
The FSM says 16-20VAC per 1krpm so at idle I should have 16-20V, and 2krpms I should have 32-40VAC.

Soooo it's a bit out of spec. My friend I bought it from never noticed because he always kept the RPMs above 4k, and I cruise around 3k so I started to notice the charging problem.

Pulled my regulator off just to be sure and didn't see any overheat bubbles on the potting (?) material on the back of the regulator. It was cracked in spots but it was all still soft and pliable. All of my connections looked good still.

Booooo.