Another fuel pump thread-Mikuni

Discussion in 'Dakar champion (950/990)' started by Kawidad, Apr 8, 2007.

  1. Kawidad

    Kawidad Long timer

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    In conducting my own research for a better fuel pump I have been reading about how people have been exploring alternatives. It has been mentioned in several other threads that Mikuni produces several compact vaccum powered fuel pumps that could be a possible replacement. After researching this issue, I don't believe that any of them will work. Their flow rates are too low and presumably the pressure will be too low as well. (0.06 gallons/minute for the most promising unit)

    The NAPA and Facet units are still the best so far, but who knows there may be others out there.

    I still looking around and will post more as I find more solid information.:norton
    #1
  2. cpmodem

    cpmodem Orange Caveman

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    :clap
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  3. Pointman0853

    Pointman0853 Unregistered Gun Owner

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    Already over done...:D

    Pointman

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  4. cpmodem

    cpmodem Orange Caveman

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    There can NEVER be too many polls :pot
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  5. idahoskiguy

    idahoskiguy Long timer

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    The flow rate on the Mikuni pump would be more than adequate for the LC8 since one Mikuni vacum pump supplies the fuel for three 44 mm carbs on my 1,000 cc triple cylinder mod motor in my modified snowmobile. It uses fuel at the rate of 8 mile per gallon when running hard, so 30 - 40 mile per gallon should not be be any problem for the vacunm pump. And in thirty years of snowmobiling I have never had a vacum pump failure, so they seem to be very reliaable.

    Just my $.02
    #5
  6. cpmodem

    cpmodem Orange Caveman

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    How 'bout a part number, ID?
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  7. cjracer

    cjracer AWD please!!

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    Where on the 950 can you hook up to a vacuum pulse, like you get w/ a 2-stroke crank pulse? The fittings below the carb that are normally plugged or capped are a constant vacuum, I believe.:ear

    How does the 640 ADV work the pumps. Do we need to do some drilling into the crank area? :evil
    #7
  8. Pointman0853

    Pointman0853 Unregistered Gun Owner

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    No, the problem is too many TROLLS...:rofl

    Actually, I looked into using a 640 Mikuni Fuel Pump in the beginning, but the Facet was way too trick to overlook.

    Vacuum from any one of the intake manifold fittings should be enough to run it.

    Pointman
    #8
  9. LKN4DRT

    LKN4DRT Relocated

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  10. idahoskiguy

    idahoskiguy Long timer

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    I was just guessing that the vacum pulse would come from the intake manifold - do not really know if this would work. Does anybody run a vacum pump on a four-stroke? On a two-stroke the crankcase provides the vacum pulse.

    Will check on a part numbers and report back.
    #10
  11. Head2Wind

    Head2Wind MotorcycleMayhem

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    these "vacuum" pumps require a pulsed signal to operate. I do not know if there is enough signal swing (positive to negitive) available at the crankcase on a 950 to make them work properly.

    EDIT: oh, and as a alternate: http://www.aircraftspruce.com/catalog/eppages/bingfuelpump.php

    flow rate should keep up with the 950's fuel flow needs.... just need to make it oscillate.
    #11
  12. cpmodem

    cpmodem Orange Caveman

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    "Somebody" needs to put a vacuum gauge on the crankcase vent. I would,butt I'm "busy." :D
    #12
  13. PowerCell

    PowerCell Manufacture Super Supporter Supporter

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    These fuel pumps run off of vacuum from the intake manifold... anywhere between the throttle plate and the intake valve. It's a small fluctuation the won't show up on a vacuum guage.
    #13
  14. uk_mouse

    uk_mouse Aquatic adventurer

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    My vacuum gauges have got little damping screws in the inputs. If I connect them up to the 950 and turn the damping right down, the gauge needles bounce around all over the place. Therefore I conclude that the vacuum from the inlet manifold does pulse, to some degree at least.

    Whether it's enough to operate one of these pumps though, I don't know.
    #14
  15. PowerCell

    PowerCell Manufacture Super Supporter Supporter

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    Early model Husabergs used this same setup to pump fuel from the lower side of their enduro tanks. The pump was mounted to the tank itself, and driven by vacuum from the intake manifold. Snowmobiles and watercraft use these same pumps as well...
    #15
  16. cpmodem

    cpmodem Orange Caveman

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    "Somebody" needs to buy one of these little jewels and hook it up to the Big Katoom, and report back to use the results. Not me, though. I'm busy :freaky
    #16