2007 XB12S burning headlights

[popeiler]

I recently bought a 2007 XB12S. It's been great fun so far, but it is burning out headlights rather fast. The first pair died the next day, and the second pair lasted about a week.

The voltages at the battery show ~14.0 volts idle, and ~14.4 at higher RPM. I was thinking that it could be an intermittent issue with the regulator. Is there anything else that I should check before throwing an regulator at it? (I was careful when installing the bulbs to not touch the glass.)

[Theycallmecrash]

Chances are its the regulator. Without a higher quality oscilloscope to monitor for for voltage spikes hard to tell.
watch for flickering in the lights while running, dim and bright Alternating.
also make sure the bulb connections are solid.

[popeiler]

I can put an o-scope on it and check. What is the maximum permissible voltage ripple for idle, and for higher RPM?

[Tbone]

Assuming Battery cables are tight? Grounds are good?
When My headlights burned out, then very shortly afterward the battery went dead. First time was 12 months, 2nd was 18 months, using a trickle or automatic charger on the battery the second time. 14 Volts is good, get the battery tested, or wait to see if it dies which I do not recommend. Even though I was stranded both times mine went dead, such a knucklehead I am.

[popeiler]

I checked the battery cables- They appear to be tight. The ground cable connection to the chassis is also tight, but I can see a slight amount of corrosion on the exposed surface of the ring terminals. Could that be doing it?

Edit: Could the '77 connector' issue that I've been reading about cause this?

Does anyone have a service manual available for this bike?

[user_deleted]

but I can see a slight amount of corrosion on the exposed surface of the ring terminals. Could that be doing it?

normally no.

Could the '77 connector' issue that I've been reading about cause this?

again, normally no but good idea to check it. it is hidden behind the front pulley cover. remove the cover(3 torx screws) and the 77 connector is identifiable by being the largest connector in the bundle and the front harness which is part of the connector is sheathed in dark cotton coated cloth material and comes from oil filter area.

a faulty VR will also give occasional DC volt spikes of 15plus volts @3000rpm. another sign of imminent VR failure is the ignition relay burning out and a subtle fluttering of the gauge needles at higher rpm's.

[Tbone]

It is too easy and cheap not to clean the battery terminals, so yes always clean them, especially when things are hokey. Take them off the battery, clean them. My first job in the military was the battery room, well actually it was to make the coffee. When you disconnect the battery put it on a bench, not the ground it will drain your battery, and test the voltage, is it 12 volts? No then put an old school, like me, charger on it for about a day. Did it go back to 12 vots or higher? Yes then go get it load tested at the auto parts store. No, put it back on the old school charger until it goes to 12 volts or you give up and get a new battery?

14 volts DC is good out of the VR, right, the battery is the final DC filter of the charging circuit. VR's all have ripple currents and the battery is what supposed to smooth it out. My unscientific explaination is if the battery cannot absorb the ripple current it fries the headlight.

[popeiler]

I took a look on the oscilloscope and have a pretty big voltage ripple. Thanks for pointing me in that direction.

[Tbone]

Almost all VR's have a ripple, the battery is the ripple filter, absorbing the fluctuations in voltage and current. If you are reading 14 V DC then I doubt it is a problem? The battery is more suspect to me than the VR, the battery has to be able to conduct at all times, due to cells sulfating, connections internally breaking down. losing grounds externally, etc...

Have you done the ground wire MOD? After this post I realized after I have done the ground wire mod my headlight has lasted a lot longer. It is also cheap and easy to do, wonder if the battery ground through the chassis to the engine is weak? If you do the MOD check it again with the O Scope and see the ripple is down. With a good battery and good ground connections the ripple should be minimized. Where is the VR mounted, engine or chassis? somebody who knows something might be able to explain the Engine(Alternator), to voltage regulator, to battery grounding scheme? On the 09 Uly the ground wire goes to the chassis under the seat to a bolt on the subframe, I think that is a Lame way to ground, especially your engine. Most cars have a big ass braided cable to the frame from the engine to make sure everything is grounded. I might be missing something but have not seen that on the Uly engine anywhere so that is what the ground wire MOD does.

[user_deleted]

Where is the VR mounted, engine or chassis? somebody who knows something might be able to explain the Engine(Alternator), to voltage regulator, to battery grounding scheme?

let's pause for a moment here and clear up some possible misconceptions regarding the grounding systems on XB's, how they work, and how the electrons flow. the entire electrical system on any XB mirrors the same system on a simple basic automobile. the electrons flow from ground to the positive source....not the other way around. the exception is the starter in "start" mode wherein the electrons flow directly from the positive battery source to ground thru the starter. the electrical system on XB's is fairly robust, very simple, and easy to diagnose problems with. the VR is mounted to a small bracket at the front of the motor. nothing in the charging system is directly grounded with the exception being the battery which doubles as a source of storage for "juice" and a giant "heat-sink" or capacitor to maintain constant DC voltage. other components such as the fan and coil for example receive their "ground" from the ecm signal. regarding the auxilary coil-pack ground cable which has been discussed at length on here, it does NOT ground the coil. what it does when typically installed is use the rear most coil hold-down bolt as a convenient fastener and is run from that point to the negative battery terminal or cable. it acts as an additional ground to engine....nothing more. hope that helps.