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ffr2370 03-13-2011 03:43 PM

Voltage regulator problems?
I have a 2008 950 SE I bought new, in 8000 miles it has been reliable as a swiss watch. Last weekend I decided to ride the Mojave Road from Barstow to the Colorado river solo, when I get to my destination at the river the bike wont restart, dead battery. Oh well, I figure the battery is toast, damn lucky I didn't get stranded in the middle of the Mojave desert! I get a jump from AAA and ride the slab 150 miles back to my truck, at about 148 miles the bike slows then sputters to a stop. Now here is where things get strange.... I hear this high pitched scream coming from under the seat, kind of like a tea kettle. Its the battery, its a tea kettle. I take it out and through it on the ground so it doesnt spew any shit inside my bike while I walk back to get my rig.

Still just asuming the battery is bad I ordered one of those bitchen new Shorai batterys and put it in. Bike fires up with authority, I do a few donuts in my pasture and put the bike in the garage and shut it off. I hear the tea kettle again, the shorai is having a meltdown....shit, that fucker was expensive and worse everyone is out of stock!

Realizing now that my problems are elsewhere I jump start the bike with the charging lead removed, I measure the regulator output and it is 25v at idle and it climbs to 60+ when the revs increase. So I'm guessing the voltage regulator is bad and caused all this mess. Does this sound like a reasonable assumption, anything else I need to check?

Another side effect is my headlight is not working, assuming that the high voltage burned out the bulb. Can a faulty voltage regulator casue any other damage or otherwise shorten the lifespan of any other critical electrical components, like the ignition or alternator?

I would love to get the opinions from those who are knowledgeble of this topic or have expereinced someting simular.



Flueger 03-13-2011 05:16 PM

My 2008 showed the same symptoms in around 10K early last year. I luckily checked the output of the regulator before I put a new battery in. The regulator was the culprit, with a new battery and regulator all is good.

A link to my battery singing in a SS bowl on the driveway, I too was lucky to get it out of the bike without incident.
http://<IFRAME height=293 src="" frameBorder=0 width=400></IFRAME>950 SE Battery Venting Gas from Flueger on Vimeo.
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cpmodem 03-13-2011 05:32 PM

ECU might still be OK since it was running when you shut it off. I'd just replace the VRR and battery, make sure of the correct voltage, and ride it to see if anything else is fried. Oh yeah, you might want to install a voltmeter on your bike somewhere where you can see it while riding. Very handy item.

Stobie 03-13-2011 05:53 PM

My SE had a bad VR from the factory. The battery was boiling after the first ride, VR replaced at 35 miles. The replacement is still good at 22k. Mine is an '07, bought new in November of '06.

KTMSER 03-13-2011 06:59 PM

I am at this point again.. 44,000 miles and going to put the fifth voltage regulator on when it arrives...

Only had one not over charge the battery, the other three boiled and ruined the batteries..

It has to be the heat from where it is located..

I have over a grand in batteries and voltage regulators this is complete bullshit...

The last two times (once being towed)I have been able to get to an auto parts store and buy a truck battery and put it on my rear rack then wire it in and disconnect the voltage regulator to get home..

The 07 and up 990's have a different VR on them, anybody know why?

Stator is good, grounds are fine..

I am at a loss here as to what is causing it, it has to be the heat from the exhuast...

cpmodem 03-13-2011 07:10 PM

Heat from the exhaust?
What bike did you say this was?

KTMSER 03-13-2011 07:22 PM


goatdog 03-13-2011 07:43 PM


Originally Posted by KTMSER (Post 15410402)

You mean this set up?

I didn't think about the exhaust heat but that may be. It get pretty hot there.

scapegoat 03-13-2011 07:59 PM

If I understood you, you unhooked the battery and ran it after it started and checked the voltage output which was 25+ Volts. If thats the case I can tell you from what Ive seen and read a bikes system changes AC to DC and if it dosent see reference point like a 12V battery it goes all over the place, This was the case on my old kick/electric XL 500. I ran it with no battery for a while and just kick started it, I checked across the leads while running once an saw similar spikes to 50+ volts. I check the grounds and positive leads on my bikes pretty regularly and find them just barely snug sometimes from th heat cycles of crankin. Might keep an eye on this as well as all the ground points on the frame etc.

cpmodem 03-13-2011 10:27 PM


Originally Posted by KTMSER (Post 15410402)

I originally saw the different part number for the SE VRR (62511034100) vs the VRRs for the rest of the LC8 fleet (60011034100) and thought it was just the longer cable that was different. Now I'm thinking it is a totally diff VRR altogether. Maybe even a diff vendor. Could be a bad bunch of VRRs and/or the extra heat of its location on the SER (yours being in AZ just exacerbates the problem) is bringing that out. I wonder if it could be relocated to a cooler location or shielded somehow. Preferably mounted to a large piece of metal using heatsink paste.

BTW, I've had good results using VRR's from this place (he has a rep for making sturdy stuff):
They aren't specific for KTMs, but I see a couple of units that should work.

KTMSER 03-16-2011 04:50 PM

Dam I have not checked back on this thread in a few days.......

Thanks for that link on the VR's cp, waiting on a reply from him...

MAXVERT 03-16-2011 05:26 PM

I emailed Tony at Oregon Motorcycle Parts about a VR for the 990 A.
He said he would like some specs on the stock regulator and a
wiring diagram.
If anyone has any of these and could send it to him it would help
get the ball rolling on what looks like a nice upgrade.


KTMSER 03-16-2011 05:51 PM

I can send him one of my old ones..

OldPete 03-16-2011 06:08 PM

A fully charged, healthy battery MUST be in circuit as it presents a ballast/load/resistance to the flow of current.
Uber-high voltage is the order of the day w/o a proper battery present.

As an imbittered old mechanic i fully expect bad news about these light weight Shorai batteries.

Turn the clock back several years...
Remember the cell phone batteries that were blowing-up in ppls pockets?
Yep. There were metal fines in the gel causing cells to dead short = BANG!

The Shorai accepts charge very fast and that generates heat. i think it does not offer the proper ballast for M/C or car use. These types of batteries are TITS for RC aeroplanes however.
Just my $0.02

KTMSER 03-16-2011 07:33 PM

Well shit.. Here is the email.

No go.

The amp rating I gave him was just the rule when converting watts to amps..

On 3/16/2011 4:59 PM,
I have a KTM 950 Super Enduro that keeps blowing VR's the stator is
450watts = 37.5 amps.

Will your VRRPM3 handle the above watts @ amps?

KTM located this VR behind the rear cylinder above the rear exhaust and
I think the heat is damaging it. I will be relocating when replaced.

If you would like pictures let me know..

I have done some checking and there are alot of them failing KTM has
changed the part numbers once with an update.
If this works out it will be an optoin for all of the 950/990 KTM's
Please let me know..



Date: Wed, 16 Mar 2011 17:53:12 -0700
Subject: Re: VRRPM3

I don't have anything that will handle that load. I do agree with you
on relocating the unit up front into the air stream. Heat kills and the
cooler it runs the better.


My reply,

On 3/16/2011 5:57 PM, >

Thanks for the quick reply. There is a market for them if you can build
What is the one for the goldwing rated at?
I could even send you one of my old ones to take a look at.
3 wires from stator, two outputs and a ground wire.


Date: Wed, 16 Mar 2011 18:06:42 -0700
> From:
> To: > Subject: Re: VRRPM3
> The 1200 Goldwing unit is only rated at 25 amps. You're not alone with
> this problem. Almost all bikes with a 30+ amp permanent magnet
> alternators eats stators and reg/rec units. Personally I think it's bad
> design.
> When I get relocated to bigger quarters, I plan to tackle the problem.
> However I'm not going to just build a bigger reg/rec unit but work on
> transplanting in an electromagnet unit of about 40 to 55 amps. At our
> current location space is so tight, I can't dig into a project without
> halting other work...
> Tony

Does anyone now the actual amps the stator is putting out?

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