ANYONE THAT IS RUNNING THE MIKUNI FUEL PUMP ON A 950....

Discussion in 'Dakar champion (950/990)' started by D-man, Oct 20, 2016.

  1. HellsAlien

    HellsAlien a has-been that never-was

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    Just another data point: been running a mikuni mounted in stock position for over ten years, about 70K miles, no significant problems or failure.

    I drilled out the vacuum fitting at the manifold to improve the signal to the pump, ran a vent line up above crank level somewhere.

    I close the fuel cock when parked until the gas level goes below carb level, no big deal.
    #61
  2. syky27

    syky27 Owner of Muller Motorsport

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    I has a problem where the bike would act like running out of fuels once there were less than 6 litres in the tank.

    Drilling the side of the engine to M6 to match my pumps Vacuum connection solved this problem.
    #62
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  3. bigborett

    bigborett Hipster Supporter

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    I was running that on the suction line when it died in the tunnel. I may have just been unlucky but I think where I have mounted it now should be fool proof fuel wise and vacuum seems fine so far.
    Just did a 1000k ride that included single track and a great little enduro loop with no issues. Was even brave enough to ride through the tunnel again. :imaposer
    It does make sense to me to have it lower than the feed.
    As @Zuber said a cool mounting position and a short vacuum line is the aim but not possible on these realistically. A short vac line means a warm mounting position.
    I'm also pretty sure that mine was vapourizing in the line also, more so than the pump.

    20200127_121001.jpg

    It is better protected there than it looks also.
    #63
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  4. Jkils

    Jkils Been here awhile

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    #64
  5. veetwo _tls

    veetwo _tls RENOVATIO:

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    #65
  6. Jkils

    Jkils Been here awhile

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    Thanks. I did a quick search in Amazon but didn't come up with much. I'll do a little more digging
    #66
  7. veetwo _tls

    veetwo _tls RENOVATIO:

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    google search then choose images go through the listings there few listed on Amazon
    #67
  8. veetwo _tls

    veetwo _tls RENOVATIO:

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    tried the vacuum pump at the lower position as posted for curiosity sake
    I got hydrolock first time since 2007
    will be placing my pump back were it was
    #68
  9. bigborett

    bigborett Hipster Supporter

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    Yes, I have just had it lock also. Didn't happen in the higher positions.
    Will still be leaving it low though. Just have to remember to turn that tap.
    Don't really see why there should be any difference in that respect, but there is.

    Maybe there is some resistance to flow in the vacuum pump and in the lower position there is enough head pressure to pass it.:hmmmmm
    #69
  10. martinbuchmayr

    martinbuchmayr Carb 950s

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    Another question I was asking myself... The pulse line of the fuel pump - Do you connect it to the crankcase ventilation or to the carb synchronisation plugs? I tried with the carb synchronisation plugs, connecting them together with a t-bracket to the pulse line like on other bikes, but it seems like there is not enough pressure to pump the fuel upwards with my Mikuni DF52-82 pump. I saw a video which is using the crankcase ventilation using a t-bracket, but I wonder if its not clogging up with oil on higher revs within a small amount of time



    Thanks for your recommendations.
    #70
  11. martinbuchmayr

    martinbuchmayr Carb 950s

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    Also I dont find any information to my Mikuni DF52-82 fuel pump, like, do I need an equalisation line between the input and output side, etc.
    #71
  12. veetwo _tls

    veetwo _tls RENOVATIO:

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    Front & rear Right side i use only for carb sync

    Back right i use for the Mikuni carb pulse line

    As for testing pump never fucked about with it never needed too , just set it up put it on as Ken & Tim done yrs ago
    #72
  13. martinbuchmayr

    martinbuchmayr Carb 950s

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    OK, so you use only one carb pulse line... hmmm I wonder if my problem is the 8mm pulse line plug on my fuel pump, which minimizes the pressure of the outgoing 4mm line of the carb pulse line... :becca
    #73
  14. veetwo _tls

    veetwo _tls RENOVATIO:

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    here some random pic i got

    [​IMG]
    [​IMG]
    [​IMG]

    vacuum line / pulse line i kept same size as the nozzle off the pump (there a wright up on this somewhere on the forum)
    fuel line i run 8mm in & 8mm out (other 2nd outlet from my pump i blocked)
    #74
  15. veetwo _tls

    veetwo _tls RENOVATIO:

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