Vapor lock on 2010 390??

it happened to me again Saturday at a race. Very dusty conditions and tight single track. I had went around 12 miles and stopped to help a buddy who had stopped. My bike was off for about 5 - 10 minutes. When I hit the starter, it started right up, idled for about 10 seconds and died like it was out of gas. I figured, no big deal, I will wait 5 minutes and it will start again. This time it didn't. It would turn over but wouldn't fire. A sweep rider finally got to where I was at and asked it I needed help. I was trying to figure out how I was going to get my bike back to the pits. It was off for about 25 minutes and had almost completely cooled down. It still wouldn't start. I tried everything I could think of. I again tried to start it, and nothing, turned over fine just wouldn't fire. Right after that attempt to start it, I turned the idle up two clicks, hit the button, and it started up immediately. I don't know it that was my problem the whole time or not. I do know that the idle seems a bit high now though. Anyway, just thought I would share my starting issues again.

The idle knob was likely just be a coincidence. When it is in "won't fire" mode, you need to listen to the fuel pump. When you release the starter button, the fuel pump should continue to make an obvious whine/buzzing for about 1/2 - 1 second. Go to your bike now, just barely press the starter button, and immediately release it so the starter just turns but the bike won't start. You'll hear the fuel pump. The next time it won't fire, listen for that sound. After you hear it once, it will be very obvious what to listen for the next time. My bet is that your fuel pump was not spinning the whole time you were in the won't fire" mode.

On another note: Husaberg better address this problem soon. There are so few of their bikes in the woods that we are very noticeable to other riders. It's really, really bad advertising for everyone to see all these dead blue bikes. My dealer says the Husaberg rep he was talking to about my problem has stopped returning his calls!! If was was in the market for a bike right now and I was reading this page, I think I'd go orange.

I did listen, but didn't hear the fuel pump. I have my rad fan hard wired on, so it is loud when I hit the button. I am going to try it at home and make sure I know what to listen for. Did your fuel pump cycle when yours was in this condition? I am beginning to think that these fuel pumps are weakening or wearing in some fashion that contributes to this. Mine didn't do this to me through the first 35 hours of use. I am at 45 hours now and am suddenly having this issue. You just put a new pump in yours and now you don't have the problem anymore.

There is definitely a problem here that Husaberg needs to put some attention to. I know that I for one am telling people about this when they ask how the berg is. I also tell them the things that are good about it, but need to mention this aspect because there are too many people experiencing this to be ignored. I am getting nervous about being too far away from my truck now. It took long enough to start this last time that I didn't think it was going to and was beginning to think the fuel pump had failed completely. It seems to be getting worse every time it happens.

JohnnyQuest said:

The idle knob was likely just be a coincidence. When it is in "won't fire" mode, you need to listen to the fuel pump. When you release the starter button, the fuel pump should continue to make an obvious whine/buzzing for about 1/2 - 1 second. Go to your bike now, just barely press the starter button, and immediately release it so the starter just turns but the bike won't start. You'll hear the fuel pump. The next time it won't fire, listen for that sound. After you hear it once, it will be very obvious what to listen for the next time. My bet is that your fuel pump was not spinning the whole time you were in the won't fire" mode.

On another note: Husaberg better address this problem soon. There are so few of their bikes in the woods that we are very noticeable to other riders. It's really, really bad advertising for everyone to see all these dead blue bikes. My dealer says the Husaberg rep he was talking to about my problem has stopped returning his calls!! If was was in the market for a bike right now and I was reading this page, I think I'd go orange.

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Hey guys, I think were missing something here. You say you would "go orange", you are orange for all intent. That's a KTM fuel pump or by product. Isn't it KTM we should really be bitching at!

You are correct that blue=orange, but I can't recall ever seeing a dead orange bike in the woods. But there are currently no FI woods KTMs.

Yes, when my bike would not fire, the fuel pump would not make any noise. Mine ran perfectly for the first 25 hours. I didn't get a new fuel pump (since they are $500!); my dealer gave me his from his demo bike that had about 30 hours on it. So far, so good.

Also, I did a search for the part number of the fuel pump and found that the same pump is in the KTM 690. I found one post of a 690 owner who had exactly the same preblem that we have. I have not been able to confirm if the new 350 has the same pump, but I suspect it does.

I talked to Lafferty's father at the last race. He says Mike has not had any problems with fuel pumps.

I am feeling a little guilty for starting this thread and not following up with anything new.I have been busy with work and have not had an opportunity to try again with the CV4 blanket installed.I have resorted to lurking in the evenings and noticed that many more of you out there have had or are continuing to have the same issue! It has to be resolved sooner or later.Has anyone had this problem crop up with an insulating blanket installed under the tank??

flyinbryan said:

I am feeling a little guilty for starting this thread and not following up with anything new.I have been busy with work and have not had an opportunity to try again with the CV4 blanket installed.I have resorted to lurking in the evenings and noticed that many more of you out there have had or are continuing to have the same issue! It has to be resolved sooner or later.Has anyone had this problem crop up with an insulating blanket installed under the tank??

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Don't feel guilty. These problems need to be resolved. Here I am sitting on a brand new bike wondering if this is going to rear it ugly head after parting with $12,000.00! Fortunately, I opted for an extended Warranty and will exercise it aggressively if need be. Hearing stories about Husaberg Reps (KTM employees) not returning phone calls to dealers regarding this, sends chills down my spine. Regardless of whether KTM's have FI or not these are still KTM parts, all of them, from front axle to rear axle. It doesn't matter which bike runs and which doesn't, blue or orange, these are KTM parts with KTM part numbers. KTM needs to a.) be aware of the problem, and b.) fix it.
As a manufacturer myself I know that lacking accountability can breed trouble. Lets hope Husaberg/KTM steps up for all of us. KA

It makes you appreciate UHE for flushing the issues out into the open.
I wonder if the Husaberg Marketing Department surf UHE?

KTM aust most definately do Look in Davo

they don't seem to do anything though maybe its just to see if we are behaving :evil:

I'm experimenting the same problem, tight single track in the woods, low gearing and high temp conditions, but the first time I'd have the start issue was when I was going downhill in a short tecnichal single track with the engine off and when I arrive to the end off the downhill I'd tried to start the engine and I couldn't, I had to wait arround 20 min and then the engine starts like always, then after 40 minutes going up hill in a tight single track first gear I' get stock in a step root and the engine goes off, then the same problem, no engine start, I'd had to wait 20 min to get it started.
That was saturday and today I took off the tank to see the filter condition and it was perfectly clean, the only thing I found out of order was that the positive pole of the batery was loose but the saturday I didn't had any issues about the starter motor so I don't know if that can do any influence in the problem.
I don't remenber if it was in this post but somebody gave some numbers about the gas pump resistance, mesuring the resistance can we know if the pump it's going to fail?

Claudio Buffardi
caracas, Venezuela

clbuff said:

I don't remenber if it was in this post but somebody gave some numbers about the gas pump resistance, mesuring the resistance can we know if the pump it's going to fail?

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The workshop manual says this:
Fuel Pump Resistance at: 20 °C (68 °F) = 1.0 ~ 1.8 ?

I don't think measuring the resistance will tell you if the Fuel Pump is going to fail. It will only confirm if the pump has failed, in some circumstances. I am guessing the Fuel Pump resistance shows open circuit when the bikes wont start, but that is a wild guess.

flyinbryan said:

Just a quick update;Took the bike down to my dealer today and coincidentally he had just received a technical/service bulletin from Husaberg pertaining to the fuel pump. He also stated that he can review all of the running history on the bike with diagnostics and can pick up on things that the basic default codes would not display.He said it should be no problem and seemed pretty confident that all will be well tomorrow.I got there right before closing so we did not look into it right away.I'll post the findings.

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Reviewed this whole thread and read this post again; KTM/Husaberg knows there's something wrong with some of these fuel pumps. Why aren't they coming clean with it and getting it resolved??? This problem is on the verge of tainting a fantastic piece of motorcycle and its already starting to scare off potential buyers as shown in previous postings.
I'm keeping my fingers crossed for my new 570.

Barshoe said:

flyinbryan said:

Just a quick update;Took the bike down to my dealer today and coincidentally he had just received a technical/service bulletin from Husaberg pertaining to the fuel pump. He also stated that he can review all of the running history on the bike with diagnostics and can pick up on things that the basic default codes would not display.He said it should be no problem and seemed pretty confident that all will be well tomorrow.I got there right before closing so we did not look into it right away.I'll post the findings.

Click to expand...

Reviewed this whole thread and read this post again; KTM/Husaberg knows there's something wrong with some of these fuel pumps. Why aren't they coming clean with it and getting it resolved??? This problem is on the verge of tainting a fantastic piece of motorcycle and its already starting to scare off potential buyers as shown in previous postings.
I'm keeping my fingers crossed for my new 570.

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I agree. I know for a fact that Mark Donovan from SOS, which is where I bought my FE 450, is a member of this site. Why aren't we getting any comments from the dealers on this? I for one am not excited about the idea of spending $500 to replace a fuel pump that is either under rated for its intended use or just plain faulty. Come on Husaberg/KTM, chime in here to give your customers some idea that you care about what is going on. I am at the point where I am thinking about getting rid of this and finding something new, or switching back to my Honda and letting this sit in the garage because I can't trust it anymore.

Well, I've had this happen again and each time I learn a little bit more. Here are the facts:

'09 570FE, 60 hours

I cannot hear the fuel pump buzz when the motor is stalled.

The gas is very hot/boiling in every case.

Usually I am at a half tank or less, or descending very steep terrain which would mimick low fuel and allow the gas near the pump to heat up quickly.

I am working the bike hard on tight trails.

The motor never dies outright, but will die a few feet after a restart, or fail to restart completely.

Disconnecting the fuel line does not help.

Adding fuel did help the one time I tried it.

I have a stock exhaust, with no fan and updated mapping.

Removing the gas cap does not help.

I do not have header wrap.

My fuel filter is not clogged in any way.


To me, all this points to one simple thing. The fuel pump has a thermal overload switch. When the fuel gets hot enough it will kill the pump until it cools back down. This circuit is only a requirement for starting the fuel pump and is not checked while it is already running. For those times when one starts the bike and it runs for a few feet, thats probably just fuel still pressurized in the line and it will loose pressure after that tiny bit of fuel in the line is burned. The question is, does the fuel pump have a thermal overload switch?

Put the fuel pump in boiling water and see if it turns on, any volunteers?

My experiences exactly. With so much feedback from the various people that are having this problem, why can't a rep from Husaberg/KTM respond to us? What, they can't even say "We acknowledge your issue and we are investigating"? One of us has even had his dealer get involved, and the dealer is getting stone walled. This is not a very good way to do business. If I was thinking of buying one of these bikes now, I wouldn't because of the apparent lack of concern from the factory for this problem.

Juicifer said:

.... For those times when one starts the bike and it runs for a few feet, thats probably just fuel still pressurized in the line and it will loose pressure after that tiny bit of fuel in the line is burned.....

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I think that's exactly right. I unplugged the connector to the fuel pump regulator (under the seat) and started the bike to see what would happen. It ran poorly for a few seconds and then died (obviously there was no pump buzz), which is exactly the way it behaved when it was misbehaving.

JohnnyQuest,

If you unplug the connector under the seat you are disconecting the fuel pump.

clbuff said:

JohnnyQuest,

If you unplug the connector under the seat you are disconecting the fuel pump.

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Yes, I know. I did it on purpose to see if it would run at all with a purposely disconnected fuel pump. When I was having the problem, some people told me that it was NOT the fuel pump since, on occassion, it would run a couple of seconds and then die. They argued that with a dead pump it wouldn't even cough. I had the same theory that Jucifer had: that it could run a couple of seconds without the pump due to residual pressure in the line. I unplugged the pressure regulator (and pump) deliberately to prove that theory.

I agree with all of the above symptoms,however the last 2 times it happened to me was under the same "harsh" conditions but while I was ridding the bike.(not a restart situation).It just"ran out of fuel"while under way.It was then that my dealer took a look at the pump and other items but found no problems.The restart issue has happened 3 or 4 times prior to that so I think that it may be getting more sensitive.Whatever "it" is!!

Re: Vapor lock on 2010 390??
Sent: %b %22, %2010 - %0
From: mootak
To: clbuff

The fuel pump test was a static psi test and a run under load test of fuel pump psi using our Husaberg psi gauge to determine the pump was operating to spec.

This bulletin was only issued from Husaberg as a test result page to be filled out if an inop. fuel pump was claimed under warranty. It was not directed at the problems you guys are having. So far every bike through the shop has been checked and all passed to OEM specs on fuel pump psi.

I race and ride the Bergs we sell, a couple years now, and have not had this problem occur to me under any situation. As a rider I am frustrated with everyones no start issue. I just beat my 2010 FE 450 for 75 miles of s**t this weekend and she never missed a beat. I am determined to find the problem.
Just a thought - My #1 fix for most Berg problems has been loose battery terminals. Not sure why, but more so than any other bike. Must be the high output and sensitivity of the EFI to voltages. One other guy had zip tied his quick connect fuel line connection up off the engine case area to tight and it tweeked just enough to stall the bike and not restart, figured the o-ring seal must have bypassed air.

The Husaberg guys are good guys, I have spent time riding and talking set-up with Nathan Woods and Charles his wrench, on a few occasions, once down in Hood River Or. we had 20 new Bergs in the tight woods and all ran perfect all day. they thrive on feedback from riders, and I have discussed this problem in length with them. So far, nothing found.
The search goes on.... we will figure it out like everything else that comes up.

Feel free to post my reply.

Later,
Jeff Tasky