Need help voltage drop

[ztied]

2006 xb12x 25,000 miles, I have the mod with the volt gauge modified in my speedometer.
Started happening slowly, usually after about 10 miles on interstate (higher speeds), Now it is more frequent.
When bike is cold, then started voltage is 12.9 at idle, then will go down to about 12.4/12.5 not lower.
It does go up to 14.4 when giving it gas,appear to work normal
Never goes over 14.4
So the issue, It will drop to like .07v ish, and engine light will come on, Bike does not stumple, and gauges still work, no dim lights.
When is wants to do it, it will lose voltage then come back after a few seconds. and keep doing that.
If it wasn`t for the volt guage, and engine light you wouldn`t feel any issues.
Vr was replaced and hard wired in many moons ago
I have tried jingling key switch, flip on and off, jingle wire harness, Of course it wont do it when parked and tools available.
Last time I rode it did it for the last 10 miles to get home, It don`t feel like battery gets drained any
I thought stators either worked or they don`t,
and seems vr usually over charged when going bad, or no charging.
I think I covered it.

 

[lancruza]

Check all your grounding points. Pull apart the grounds and lightly sand and clean all contact points. Make sure good clean contacts on the battery.

Here's a thread on the grounds.
https://www.buellxb.com/forum/showthread.php?41391-CHECK-THEM-GROUNDS

Also...

Check the 77 connector.
https://docs.google.com/document/d/1eGkF1pN1dftycPcTD-6Mb4p19gcxWvXEJcIIjEVFycw/edit?pli=1

 

[ztied]

Thanks for the fast input, I will go over the grounds
The 77 connector was bypassed along time ago.

 

[Barrett]

Mike: Thanks much for the kind "fuel pump" words.

Levan provided you a great starting point on all the grounds and yes...I've never experienced a part-time VR. Their pending imminent complete failure typically preceded by outputs in the 15-plus DC volt range or 5 volts and less and repeated popping of the ignition and/or battery fuse......all in the 2500RPM range and higher. Stator AC output tends to initially get weak as they start to age and tire....then go to zero in a very short period of time I would: Re-check your "77 Hack" work and see if all in good order....thoroughly check condition-integrity-tightness of both ends of both battery cables...load test the battery just for the hell of it to eliminate an internal shorting plate.
Mike, I would also carefully check the condition of your ECM and its connections. You know this but the seat interference situation and failure rate on 05-06 Ulysses was disproportionately high compared to all other XB models.

 

[ztied]

Thanks John, No problem on the words, Thanks for the input also. I will recheck everything

 

[Barrett]

My pleasure Mike. You can also do the old primary "sniff test" which often times reveals a stator problem. Remove either the derby cover or chain tension inspection cover and give the guts of the primary a whiff. If it smells like an electrical fire it's an accurate indicator of a failing/fried stator.

 

[ztied]

Thanks again Sir, I will look into that also.

 

[Cooter]

What circuit is the voltmeter getting its power from?

What you are describing is a short in the wiring system somewhere. Sure, could be the stator, but also could be anywhere else, including NOT the charging system.

 

[ztied]

The voltmeter is wired into the speedometer circuit board. Don`t remember which part of board I soldiered it to. I haven`t had a chance to dig into it yet

 

[Cooter]

Then I'm curious how the gauges still work with basically no voltage? I would say the voltmeter supply wires have an intermittent open inside the dash, but can't explain the CEL.

 

[ztied]

Thats what I am stuck on. I will take dash apart, and see where I soldiered to. If I soldiered to the light circuit on the circuit board, it wouldn`t affect the speedometer needles, but why the cel? And no loss of power to bike. On the dash the middle bulb is burnt out, and when I hit the horn, the bulb on the right side of the dash will flicker. So I was leaning towards ground issue. So I tried to troubleshoot some, and of course when my meter is out, it won`t have any issues.Even though battery seems good, I got a new one coming.

 

[Cooter]

Ya, thanks for mentioning the other electrical problems you have. Pop the dash apart and give it a good look-see.

 

[ztied]

Thanks for all the input, I just pulled the bike out of the garage to start tracking down the issue, getting to be time to ride. Few updates here
Upon starting bike, will show 12.9 volts, after a few seconds volts will go down to .06 ish, then come back to 12.9 after a few more seconds.
I checked and cleaned all grounds, even ran a few extra grounds.
I cut red wire on the vr, this shows 16-19 volts. The bike still does the above with this wire cut.
Plan on changing the vr today hopefully, but with this cut, and the voltage is still dropping for a few seconds everytime after key turned off/back on.
Cel does come on while this happens, could a relay cause this? Or ecm.
The bike will drop voltage like that when running or with key on not running,
Sorry tried to keep this short and direct

 

[34nineteen]

The CEL is probably just coming on to indicate the low voltage.

The red wire showing 16-19 volts is not good. The VR should be limiting it to 12-14ish.

Did you clean the connections where the subframe rails attach to the main frame? That usually gets overlooked. It doesn't sound like you have a ground problem but more of a VR getting ready to die problem. The volts going down to .06 sounds like something is shorting out (possibly the VR). Be careful, as the over (and under) voltage problems can cook the ECM.

 

[ztied]

It almost does it like part of a functions check, like when you start your car, and it runs through the tests, The Grounds recleaned, and have multiple extra ground wires run, as a secondary ground in case of bad frame grounds.
I did change the voltage regulater. Funny thing is the built in (dash mod voltage guage) never showed over 14.5 ish volts, only when I cut the red wire from vr, and measured on the vr side it hit the 16v`s.
I have also checked on the bak side of fuse panel, with test light, and all of the relays have power, when voltage drops.
I am going to try my spare ecu, and maybe another speedo. It happens to consistently to be a bad ground( imo)
also if key switch was acting up seems it would make more things act up?
Havent test drove yet after vr change.
Thanks for input 34nineteen

 

[ztied]

Also like cooter suggested, almost a small part of me is thinking dash or my dash mod guage is acting up. I will also check that.

 

[Barrett]

Mike: 1- Pretty simple process to figure this out. Attach a known quality multi-meter to the battery terminals and secure the multi-meter in a position so that you can read it when activating key on...kill switch on...cranking engine. If meter displays what is traditionally acceptable voltage during your start-up process then it is the cluster mounted volt gauge at fault.

2-multi-meter displays the same type of voltage behavior the dash gauge does during start up followed by wildly erratic voltage output then most likely the VR is at fault.

#1 has no effect upon the ECM nor will it store a fault code for #16 nor will it activate CEL
#2 will store and activate

 

[ztied]

Thank you Barrett, Good advice, I will check that next time I get a chance to work on the bike

 

[ztied]

So finally an update, I am convinced,it is in the speedo cluster. I put a plug in voltage tester in the cigerrette lighter plug, and it stays at normal voltage, while the built in one goes to .02v then back up to normal voltage. I haven`t taken the speedo off yet to check the wiring for the built in voltage guage. Hopefully more soon.

 

[ztied]

so it appears 1 of the wires to the voltage meter (voltage meter mod) got smushed under the cover, and was pierced on a solder point.

Can the speedometers be swapped around and register the right speed/tach/mph? Asking for a friend