Fuel starvation KTM 990 Adventure

Discussion in 'Dakar champion (950/990)' started by david290361, Jan 6, 2020.

  1. david290361

    david290361 Adventurer

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    View attachment 2072258 Hi All, old member returning after a long break.

    I have a KTM 990 Adventure 2009 model. About 60,000 km on the clock now. I bought this bike used about 20,000 km ago. Shortly after I bought it, on a very hot day it had an issue like fuel starvation... when I opened the fuel filler caps it sucked in a gutful of air - then immediately started and ran a whole lot better.....leading me to self diagnose blocked tank vents tubes.

    I pulled it apart and found that this indeed was the cause of the problem. It appeared that someone might have had the tanks off and inexpertly re-installed them or the breather tubes, causing them to become kinked and squashed flat. I cut out the flattened parts of the clear PVC tubes and re-joined the ends of the tubes together with pieces of stainless steel tube I had laying around....

    A few months later I shipped the bike to Europe and rode it from the UK to Turkey via Serbia and Bulgaria then back to the UK via Romania and the Ukraine... without any problem.

    At all.

    Now it is back in Australia and the other day I rode it to work with no problem, parked it up all day and then when I tried to ride home it would fag out after about 300 metres with fuel starvation symptoms. It was again a very hot day....

    I opened the fuel filler caps but no instant joy this time....

    I think the temperature is significant because, though it has only happened twice, it happened on stinking hot days. The most recent was 46C or a mick hair less than 115F

    I have just gotten off the 'phone to a KTM workshop nearby and after their service manager utterly failed to impress me with his need to talk over the top of me rather than listen to what I was saying, I have decided not to take it there for a $150 per hour problem fishing expedition....

    A quick look on the internet found only that KTM fuel pumps can be problematic and that they have a non serviceable fuel filter incorporated into the fuel delivery pump...

    I am planning taking the bike to the USA, Canada and Mexico in about April 2020 and rather than allowing this arrogant stealership to fleece me, I would ask anyone with similar experience what they have done when faced with similar symptoms?

    Any and all suggestions will be gratefully received.....

    David
    #1
  2. kelly007

    kelly007 Adventurer

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    Hi,

    The fuel filter is serviceable. You get a kit for it. There is also an inmate that does a cheaper version than ktm. Just involves removing the left tank, pump, and replacing. There is a paper type filter as well as a sock type. You replace both as well as a oring or two.

    I would start there if you believe it to be fuel delivery related.

    Kelly
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  3. david290361

    david290361 Adventurer

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    Thanks Kelly,
    It seems almost certainly fuel related.

    I have started the bike again now that the days are cooler (29C), and it seems to run fine but I am reluctant to ride it anywhere in case it means pushing the thing home again... It will happily idle now for more than 15 minutes in the driveway, whereas on a really hot day it will starve for fuel within a few minutes.....

    I turn it off when the cooling fan kicks in...

    It is definitely a fuel issue but, also seems to be temperature related too...

    One other thing I forgot to mention was that I had re-fuelled the bike immediately before each time it "broke down". On both occasions, the fuel level in the RH tank was close to overflowing while the fuel level in the LH tank was a couple of inches down from the filler neck. The tank equalising valves (above the bash plate - base of radiator) have never been closed

    A further search of the ADV rider site turned up a non OEM kit that someone will ship for about 22 Euro. Presumably this is domestic shipping to Europe.
    An Ebay search also turned up another kit that would cost me US$100.00...

    The Service Manager at the dealer told me that it was a "non serviceable" part. He also was very condescending and when I said that high temps should not stop a bike that regularly cleans up on the Paris-Dakar, he said that it never gets close to 46C in that race.

    I don't think he even knows where Dakar is!!!

    Thank you for your reply, I don't need to ship my bike for a few months.... I will see what other replies I get and then buy a filter kit.. it can't hurt....
    Thanks again!
    #3
  4. GSpear

    GSpear Adventurer

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    #4
  5. kelly007

    kelly007 Adventurer

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    Not applicable to the 990. 950 only. (Dr beans that it)
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  6. Salzig

    Salzig Long timer

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    #6
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  7. david290361

    david290361 Adventurer

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    Thanks everyone... filters will be changed. I copped some fuel of variable quality in a few places in Eastern Europe.. in the back-blocks of Ukraine in particular...so they are probably due a change anyway....

    This service manager idiot struck me as just an arrogant so and so. Like he thought his poo did not stink.....
    It takes all kinds to make the world go around.... I have already PM'ed Gefr asking if he can send me his kit from Greece.

    If I can work out how to do it, I will post a few pics of my travels.... soonish...

    David.
    #7
  8. gefr

    gefr Life is a trip

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    Hello there,
    Heat plays 2 roles. The one is the breather hoses get soft and can clog, even though in colder conditions they wouldn't.
    The other is hot fuel is more prone to evaporate inside the fuel pump, as the pump tries to suck fuel, reducing the pressure topicaly. So cavitation happens and fuel does not flow. Cheers
    #8
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  9. GSpear

    GSpear Adventurer

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    Ah. Thanks for clarifying, I thought it had the same pumps....... good to know.
    #9
  10. david290361

    david290361 Adventurer

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    Thanks. I noticed the soft clear PVC tubing that had been used for fuel tank vents did not appear really fit for purpose when I did the repair before, and the path these tubes passed through were quite torturous. But as the tanks did not suck in air when opened and the engine again would not start even with the fuel filler caps open at the most recent break-down I think that the fuel was probably evaporating inside the pump.

    This surprises me as at 46° C, it was awfully hot but not Sahara Desert hot..... Really surprised actually.....

    I will do the filter thang and just monitor the problem.... and hope that it doesn't happen again in the future.
    #10
  11. Salzig

    Salzig Long timer

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    Sounds suspicious, as far as I know venting hoses have always been black and pretty stiff.

    For your information, there are 3 venting fittings on each tank:
    - top inside one connects with its brother on the other tank for pressure equalizing
    - middle inside one is the fuel overflow drain, comes from near the fuel cap
    - front top one is the actual venting hose
    #11
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  12. david290361

    david290361 Adventurer

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    Thanks Salzig,
    It was the second one you mention that was the problem before:

    - middle inside one is the fuel overflow drain, comes from near the fuel cap

    The tube looked like crap, really cheap and nasty....I will have a look at the service history on the bike. Maybe the pretentious dealer may have replaced the vent tube at some point.

    Probably 3 people work there but they still had one of those "Dial 9 to go around in ever decreasing circles until your brain falls out" telephone answering things...
    Thanks for the heads up. I will investigate further.....
    #12
  13. Zuber

    Zuber Zoob Supporter

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    Ditch the clear pvc hoses. They don't like heat or fuel and will cause endless issues.
    The front top vents are the important ones.

    The best routing (that KTM finally went to) is to run a black hose from one side to the other. Route it through the fairing just below the instruments.

    Put a TEE in this hose loop. I put it just on the RH side of the instruments, because this is the highest point when the bike is on the side stand.

    Point the TEE up and put a vent hose on it. Route that vent hose up high as possible in the fairing and over to the LH side, down to the skid plate.

    With this routing I've never had the tank over flow when one side gets hot.

    Your other problem is probably the fuel filters. I always carry a filter kit on long trips and have changed them in a hotel parking lot. Plan on doing filters at least every 20k miles.

    If you travel through Western Oregon, stop by.
    #13