Alternative fuel pumps for FI KTM990

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by cjracer, Jan 9, 2009.

  1. cjracer

    cjracer AWD please!!

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    I've been held up getting back to this project. If anyone has a bad stock 990 pump that is willing to send it in, I'd like to take one apart.

    I've got a few 990 tank blank off plates to swap on an external pump in the works. Keep you posted w/ updates.

    Has anyone installed one on a 990. I'm looking into making a fuel tank adaptor plate to use a pump on a FI bike and just want to make sure it would work first. Much cheaper than replacement KTM pumps.

    I'd like to mount it outside the tank in the area that the 950 fuel pumps were mounted.

    I'm sure it's only a matter of time before these start to go. FI is here to stay so let's deal w/ it.

    I'd hate to be in the middle of nowhere and have to drain my tank to pull this pump.

    I don't have a 990 to work w/ or on so that's where I need your help.
    If you think it's a waist of time say so.

    Stock pump:

    <TABLE id=searchresults width="100%"><TBODY><TR class=odd><TD align=center>61007088100</TD><TD align=left>FUEL PUMP 06</TD><TD align=right>$540.00</TD></TR></TBODY></TABLE>

    I'd think if an external pump for about $75-100 would work, a regulator if need be and an adaptor plate would work for about $200-250 it would be worth while. From then on all you would need is a new pump if it fails.

    :ear
    #1
  2. Yzlvr

    Yzlvr Been here awhile

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    I like the idea, I have the 990, maybe tahoeacr can help.
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  3. Head2Wind

    Head2Wind MotorcycleMayhem

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    What is the fuel rail pressure set at on the 990? usually on most modern cars it is ~40psi or so. I don't think that it does any dynamic pressure regulation either.

    something like this Summit pump universal unit

    and a regulator
    #3
  4. 990S Pilot

    990S Pilot Is this round trip?

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    I don't think it'd be a waste of time, I'm interested in a cheaper solution. Since this is a potential failure point I'd like to have a relatively inexpensive solution I could carry as a spare to more remote areas.
    #4
  5. aurel

    aurel Cheese&Wine!

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  6. Head2Wind

    Head2Wind MotorcycleMayhem

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    I fixed it....
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  7. Head2Wind

    Head2Wind MotorcycleMayhem

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    From what I have found so far, and I have been looking at this for the non EFI (950) for a while now, it is going to be ~300 or so to come up with a complete replacement solution with a external pump with return fuel regulation inclusive of a interface plate for the 990 fuel tank. it could be field installed, however I think that replacing the stock system with a improved external system would be my preference rather than trying to fix it in a remote area.

    total system components:
    fuel pump: ~$100
    regulator: ~$100
    990 tank plate: ~$50 (total guess)
    fuel filter: ~$20
    various fittings and hoses: ~$30

    thoughts CJ? am I way off costs? is there another way?

    I know that the FI in my old CBR600 FI tank mounted pump (and many other M/C systems) just dead headed to the fuel rail without return fuel to the tank like in a car, so maybe return fuel and adjustable FPR is not necessary.
    #7
  8. Dusty

    Dusty Long timer

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    :ear .....:lurk
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  9. cjracer

    cjracer AWD please!!

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    Ya, I guess you're correct. I didn't figure in the fittings, filter and stuff.

    This is what I made to fit my Aqualine tanks after finding the the peice of inner tube rubber they give you as a seal failed, only to find about 5 gallons of fuel on the garage floor in morning. Good thing I don't smoke.:kboom

    I'm not 100% sure this would fit on a 990, but it work on these tanks meant to fit the stock pump.

    After looking into the cost of materials and time, about $50 sounds real close for the plate and viton O-ring.

    An older model pump from a FI sport bike like you said might work.

    If someone needs a plate and wants to run w/ this idea testing pumps and whatnot let me know. I could make another up for test purposes, before I make a larger batch.

    I would think that this "kit" would be put on "Before" the stock dies if heading out on a long trip. If anything just carry another pump, easier to install like the 950 version.

    Would something like this bolt on to the stock tanks?

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    #9
  10. aurel

    aurel Cheese&Wine!

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    I think it would fit.
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  11. amaunu

    amaunu Been here awhile

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    Does Facet have pump in their production line? I guess FI is not that sensitive to pressure variation if flow rate and adequate mean pressure is achieved. What is good for aeroplane is definetly out KTM engineers mind.
    #11
  12. gefr

    gefr Life is a trip

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  13. PowerCell

    PowerCell Manufacture

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    Try finding a Bosch FI pump off a '68 or so VW Type-III. They are a remote mount pump with a return ciruit that allows excess fuel to be cycled back through the tank to prevent vapor lock. All you will need is a return line to the tank - which should be easy.
    #13
  14. cjracer

    cjracer AWD please!!

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  15. PowerCell

    PowerCell Manufacture

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    Nope. The beattle was carbed. Try a 73 S-bug, I think that's when they went FI...
    #15
  16. tahoeacr

    tahoeacr Long timer

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    O.K. Here's what you need to know. Fuel pressure is 3.5 bar(51.45 psi). As the voltage changes on the fuel pump so does the pressure. As pressure changes, so does flow. A pump flowing say 30 litres at 50 psi does not flow 60 litres at 100psi. As pressure goes up, flow rate goes down. Flow rates change and your air/fuel ratio changes. The ECU has no clue if your pressure changes. This is the reason for a pressure regulator. All FI systems have them. Current train of design is the fuel pump module(in tank) has the pressure regulator built in. This is known as a "dead head system". Only one fuel line is then required to head up to the engine. With aftermarket set-ups, you need to plan that the return line does not come back in where the pick up is. The fuel pump will be stronger than stock. You can have enough pressure from the return line to blow the fuel away from the pick up under high g-loads and low fuel. This doesn't happen with fuel tank modules cause the pick up is in a seperate cause inside the module. It's designed to stay full. The return will be in the outer case.
    I'll pull my tanks off tonight and see if I can come up with any helpful suggestions. I'm thinking to mount it with the crossover tube in the front bottom being the draw. Get more usuable fuel that way. Return could go in and regulator be mounted where the stock pump was. That way you have one fuel line coming up the left side to the regulator. Return go right in the tank and not have another line running around. Stock line go right to the regulator at the stock pump location. Keeps the new fuel line short=less$$.
    An adjustable pressure regulator would probably be a good thing for all these 990's running around with crappy fuel milage.
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  17. Yzlvr

    Yzlvr Been here awhile

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    Now we are talking!
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  18. tahoeacr

    tahoeacr Long timer

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  19. gefr

    gefr Life is a trip

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    If it is easy, could be worth it to get the OEM fuel pressure regulator with OEM pressure output with $0 expense. Is this a KLR approach? Cheers.
    #19
  20. Head2Wind

    Head2Wind MotorcycleMayhem

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    Hey Tahoeacr Thanks for the details! I suspected that the fuel pressure was being dynamically altered by the ECU via PWM. I like the idea of putting/mounting the FPR directly to the adapter plate (if there is room). that way the fuel comes from the x-over, through the pump up to the fuel rails then down to the return point on the left fuel cell. although with unit pictured (that normally attaches to the end of the fuel rail) it would need to have some sort of attachment/fixture/fitting to allow it to be attached to a hose coming from the fuel rails.

    I know that my neighbor's twin turbo Mitz 3000 gt has a ECU modulated fuel pump, plus a bunch of other crap. My Subie turbo fuel pump system is fixed voltage with a 1:1 FPR.

    I guess that we would not need to have any vacuum/manifold signal to the FPR and let the ECU control the FP as per the stock setup.....
    #20