Vacuum fuel pump for 950

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by MT950, Jul 27, 2009.

  1. MT950

    MT950 "OLD" Adventurer

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    Jan 15, 2007
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    montana
    Did a search here,and found some info. but topic stopped in 07. Anyone, here running a vacuum fuel pump conversion kit (like the one Alternate Cycles carries) on their KTM 950 Adv. ? If there is a thread for this, please steer me that way! Thanks for any info. or feed-back.
    #1
  2. kennyd

    kennyd kennyd

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    any questions? i have many bikes with 10,000 klicks on the kit! www.alternatecycle.com always turn off your gas tanks overnite as it is possible to hydro lock if the tanks are full and tanks vents are not working!
    #2
  3. 950TRANSALP

    950TRANSALP Been here awhile

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    Do you use both fuel outlets or just one ?

    My bike ( home brew w Mikuni )works great unless pulling a long fast 80ish uphill , it seems to run out o fuel , just cuts out for a second , other wise it's fine .

    Certainly it looses vacuum under big loads , aka vacuume wiper
    #3
  4. kennyd

    kennyd kennyd

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    i use both outlets 1 to each carb but that is not your problem your vacuum fitting is too small and doesnt keep up to your fuel consumption! drill out the fitting min 9/64"
    #4
  5. 950TRANSALP

    950TRANSALP Been here awhile

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    You'r right the vacuume fitting I used was that brass fitting with the tinny hole .

    It's reasuring that no fuse - points - electic motor to worry about .
    I did get hydrolock in New Mexico on the centerstand , had to remove the rear plug to get the fuel out . Pushing in gear didn't work .
    Now I just turn off the valve at night with a full tank .

    No valves any more on the tank vents .

    Thanks again Kennyd !!:freaky
    #5
  6. 950TRANSALP

    950TRANSALP Been here awhile

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    Will your kit work with a 990 ?
    They seem to be having fuel pump probs too ...
    #6
  7. kennyd

    kennyd kennyd

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    no the 990 is a completely different system with high fuel pressure over 60lbs and controls the fuel curve ! thsi low pressure kit is just to keep the float bowls full.
    #7
  8. Hank.SD

    Hank.SD Jet Measurer

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    Is there an aftermarket solenoid operated fuel shut-off that would go well with this pump? I think Moto Guzzi's have an electric shut off petcock. Turn off the key and the fuel shuts off.

    I like the idea of this pump better than the stock or alternate electric ones, but I think turning the fuel off manually would be a PITA that might easily be forgotten at the wrong time.
    #8
  9. Hank.SD

    Hank.SD Jet Measurer

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    Something like this...

    http://www.dan-marc.com/79-afc11112.html

    12 Volt Multi Fuel Shut Off Valve

    [​IMG]Item# 79-AFC11112
    Regular price: $29.87
    Sale price: $25.65
    Availability: Usually ships in 2-3 business days.
    #9
  10. dieterf

    dieterf dieterf

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    May 9, 2007
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    I have used the alternate vacuum option for 700 km's now. Bike runs great, no issues at full throttle acceleration nor full speed. i do close the fuel taps,as after a refill i left them on at the office for a full day and i suspected a tad of hydrolock, I battled to start and the bike ran very rich for a while. i now run one side tank closed all the time, unless the level is low as the reserve is halved. This eases closing the taps near the header on the right side. am contemplating fitting an inline stopckock into the carb supply line, post the t junction and the tank. battling to find a suitable unit though.
    #10
  11. Hammer

    Hammer Hawlin' aZZ

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    I have a Mikuni vacuum pump on mine, and have for near 2 years now. It's not a kit, but likely the same pump.
    I only use 1 outlet. The pump volume is the same with 1 outlet or 2, and far exceeds the 950 fuel needs in either case.
    There is potential for fuel flow with engine off. I have not been able to stop that. I use the petcock to prevent hydrolock, and if I forget, push the bike backward in 6th to "unlock" it.
    #11
  12. FINNDIAN

    FINNDIAN Mine goes to 11

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    I like the idea of a vacuum pump as they almost never seem to fail.
    Would mounting the pump high on the bike help the hydrolock problem.
    These pumps seem to have some resistance to free flow.
    Strange the needle and seats in the carb don't prevent a hyrolock. The fuel should run out the carb overflows before into the engine if the needle and seat aren't doing their job.
    #12
  13. jackr

    jackr 2008 KTM 950 SE

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    There seems to be something funny happening here. I have had Keihin carbs on all the different brands of bikes I have owned and have never shut the fuel off on any of them. Why are the KTM Keihins passing fuel?
    #13
  14. Hank.SD

    Hank.SD Jet Measurer

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    I think this winter I'll fit a vacuum pump with the electric shut-off valve. Should be reliable as an axe and simple.

    No one else has tried a fuel shut-off valve like the one above?
    #14
  15. jackr

    jackr 2008 KTM 950 SE

    Joined:
    Aug 25, 2006
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    Kamloops BC
    I would like to put a vacuum pump on my bike but I don't want to have to close petcocks all the time, especially those useless pain in the ass KTM petcocks. The Keihin carbs on the 950's are different then most bikes because the air travels vertically through them and the float bowls are on an angle. If we can find out why fuel is flowing through the carbs and hydro locking the motor maybe we can find a cure to the problem.
    I can think of only 3 reasons why fuel will flow through the carbs:
    1: The float valve is not sealing. I don't think this is the case as the bike would not run right with a faulty valve.
    2: Because the bowls are on an angle I wonder if the fuel is able to flow through the jets and into the engine when the bike is shut off? When my bikes sits for a while the stock fuel pump runs for a while on start up. This could be an indication of the fuel flowing through the jets and emptying the float bowl. There is probably not enough fuel in the bowl to cause hydro lock as long as the bowls cannot refill.
    3: The fuel tank is pressurizing and overcoming the float valve forcing fuel through the carb. I believe tanks pressurizing were a problem on Adventure models and some guys did a flapendectomy as shown in HOW to solve the problem. It would be nice if the hydro locking problem could be solved by just doing a flapendectomy. I'll have to check the cap on my SE and see if I can blow air through it.
    Any thoughts?
    #15
  16. ktm950se

    ktm950se Banned

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    That's a great find, thanks! :clap

    ktm950se
    #16
  17. ridewestKTM

    ridewestKTM Long timer

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    Mounting high will not help hydrolock -it will syphon just like any other system unless you are way high. And high will promote vapor lock - thats when it IS high enough.
    #17
  18. crofrog

    crofrog Long timer

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    The carbs on a 950 are mikuni bst40's not Keihin.
    #18
  19. Hank.SD

    Hank.SD Jet Measurer

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    I haven't ordered that or the pump yet, but they are both on the must-do list this winter. I've only got 7500 on the stocker, so I'm not concerned yet but I do want to upgrade to something around 10K. I really like the idea of a vacuum pump much better than switching to a Facet.

    Let us know how it works out if you try that shut-off! If I'm the guinea pig first, I'll certainly report back.
    #19
  20. MT950

    MT950 "OLD" Adventurer

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    This is why I posted this thead!!!! I plan on installing a Vac. fuel pump, and wanted some feed-back. Keep the Questions/info. comeing!! It seems I am not the only one looking for more info. Seem's the way to go, but all info./input is helpfull !! Thanks!!
    #20