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. D-man

    D-man SALLGOOD

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    I am thinking of converting to the vacuum fuel pump, it seems the best place is at the stock pump location and add a solenoid shut off valve. BUT I am concerned about the pulse vent hole on the pump during water crossings, anyone have any issues with that? seems like it would plug and or suck in some water and cause some issues with pumping.

    any other issues over the long haul I should know about?

    Thanks
    #1
  2. gearheadE30

    gearheadE30 @LC8Adventures Supporter

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    I guess I struggle with bothering with that when the stock pump with the Dr. Bean optical mod works great, and is far less hassle to set up.
    #2
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  3. rinho

    rinho Rinho FĂ©roce

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    So do I, very happy with Dr Bean mod, since 35 or 40K Km, easy and reliable
    #3
  4. Boatman

    Boatman Membership has it's privileges ;-) Supporter

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    He said in another thread that is would cost him over $200 to go back to the OEM w/Beans.

    To answer the his original question... yes, water getting in the vent will cause the pump to be less effective and possibly stop working.

    I've know 2 people that went with the Mikuni only to go back to the OEM pump after a short period for various reasons.

    My suggestion would be to pick up a take-off pump from eBay for $25-50 and then install the Beans. And as I have done,,,, a second pump and install new points. I always carry a second pump on the bike (Adv and SE). Every 20k miles I swap the pump and if the pump needs new points I replace them at that point before they fail. The only actual OEM failure I've had was with my first SE. The pump locked up on a mountain in Colorado.
    #4
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  5. D-man

    D-man SALLGOOD

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    if I could turn back the clock I would totally do that.. I cringe at the import knock offs and would not trust my butt to rely on it 100 miles from nowhere, BUT I burned the bridge so to speak and modified the battery box mount and installed a Facet which failed after 3000 miles. I also like my new hose set up where I can run from both or either tank and shut off the other one if I needed to

    I jumped in and purchased the vacuum pump and solenoid already so now to go back would be a $300 move. so I though I would try the Mikuni first. some of the issues based on others failures/experience is the distance from the vacuum source. if you go more than about 1 foot, the tube needs to be very rigid. so I think I will use copper for the long run and very short rubber vacuum hose on the ends for the connections. Solenoid should solve the hydro lock issues and putting it in the oem spot should eliminate the vapor lock problems when placed up by the air box. I would also run a tube up to the top of the frame for the pump vent. then it could run totally submerged.

    I really like the reliability and repair-ability of this pump, the rebuild kit is very small and a Philips screw driver and 20mins will fix it.
    #5
  6. twobarb

    twobarb Adventurer

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    Somewhere I read a good idea to use one of the vacuum operated fuel shut off valves from the emission control stuff we all took off. Eliminates an electric solenoid.


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    #6
  7. D-man

    D-man SALLGOOD

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    I read that also but my 950 was desmogged when i got it so no sas parts laying around.
    #7
  8. twobarb

    twobarb Adventurer

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    What if you ran 1/8" poly tube instead of copper? It would be lighter and easier to route. I'll be following your build as I've been considering doing the same.


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    #8
  9. Qwik

    Qwik Adrenaline Addict

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    I had the mikuni for a while. You need to close the petcock off every time you park it for more than an hour. Or learn to put the bike in fifth gear and roll it back a few feet everytime you forget.
    #9
  10. hotrdd

    hotrdd Been here awhile

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    Why not throw in a facet fuel pump. They are cheap and reliable.
    #10
  11. D-man

    D-man SALLGOOD

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    I installed a facet 3000 miles ago and it crapped out just now that is the reason for the change, I guess others have had good luck but not on mine. at this point it costs more to go to an OEM with the Dr bean mod but I may end up with that anyway I do like the simplicity of the vacuum option. I am installing a solenoid for the shut off.

    Apparently if you get over 12" away from the vacuum source you start to lose some of the pulse signal and thus it does not pump as good. you need to use a tube that is ridged to transmit the pulse to the pump. there are stiffer wall vacuum tubes but a 1/4" copper tube is not a big deal and is very good to send the signal down to the OEM location. probably not needed but I am anal about things like that if I can make it better I will try at least. I will report on the success and or failure.
    #11
  12. ridewestKTM

    ridewestKTM Long timer

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    Hey Dave: Why not discuss this with me?! We chat about everything else.
    #12
  13. ADV67

    ADV67 Alsace rider

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    Never had that problem with my Mikuni vacuum pump over he last 3 years and I leave the petcocks open - all the time.

    [​IMG]
    #13
  14. Qwik

    Qwik Adrenaline Addict

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    I had that happen repeatedly.
    I was on a 950Adv with Safari tanks and the pump mounted low. Not sure if that's relevant but the DFS21 pump does NOT have a check valve
    #14
  15. godzuki

    godzuki live better speed more

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    I have a huge fcker of a vacume pump mounted to the back of my air box, its the reason my bike kept randomly dieing, but I didn't know I had a vac pump I thought I had a oem because I was new to these bikes. I bought a cjd facet kit and started right in.......wait weres the stocker it clearly says its mounted right now here under noooope I followed the lines and that is mounted on the back of the air box. so I capped all its holes and finished up the facet kit. I was going to uninstall it but it does work so ill keep it mounted as a back up.
    #15
  16. twobarb

    twobarb Adventurer

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    #16
  17. MultiDoc

    MultiDoc Been here awhile

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    I have the vacuum pump from Raid Designs, no problems at all. I'm thinking of getting a service kit for it just in case, to carry with me. Anyone knows where I could buy one ? Can seem to be able to find it :(
    #17
  18. twobarb

    twobarb Adventurer

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    Jetsrus.com has them.


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  19. D-man

    D-man SALLGOOD

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    well finally had a hot date with my true love and discovered the whole pump deal was MY BAD! the facet was totally OK. was a kinked hose!.. (dont you just hate it when your hose gets kinked?:) ) When the fuel line leaves the pump it take a quick 90 to go up to the carbs. I had a little too much slack at the 90 and the hose seemed to be softer than the average rubber fuel line. my big surprise is that it took 3000 miles to show up you would have thought it would be on the first trial run. so I am leaving the Facet as the main pump and since I bought it I am adding the vacuum pump as a built in spare, will hook it up with a fuel valve and only plug in the vac line if I need it. so for convenience I am putting the vac pump on the back of the air box. be a good way to test it too only have to turn it on and pull the fuse on the facet and see how it goes.
    #19
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  20. twobarb

    twobarb Adventurer

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    Find a spring with a slightly smaller ID than the OD of the hose. It'll keep the kinks away.


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    #20