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Thread: Header tanks and fuel starvation

  1. #1
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    Header tanks and fuel starvation

    I have a GS1100 and the original builder installed a 2" x 6" header tank. I have a Facet 40163 fuel pump that puts out 1.5-2 1/2 PSI and 17 GPH.

    The problem is I'm experiencing brief fuel starvation in really tight, long turns. I've considered reducing the size of the tank and turning it vertical instead of horizontal. But I can't help wonder if the fuel loss isn't happening in the carbs cross feed tubes.

    Do you guys use header tanks or do you plumb the pump directly to the carbs? How do you solve this problem?
    Ken: Suzuki '80 GS1100 Sidecar || Hack Nutz Racing (HackNutzR.US)

  2. #2
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    Wouldn't the starving have to start at the pump? Chuck a baffle in the tank.

  3. #3
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    we had the same problem, had a feed to each pair of carbs from each end, on long corners it would surge to one end and feed the outside set of carbs, cured it by putting an x in the middle so both ends fed to x then from x to both sets of carbs.

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    Quote Originally Posted by Drew View Post
    Wouldn't the starving have to start at the pump? Chuck a baffle in the tank.
    Na, its not like a fuel injection system. its just a low pressure pump supplying carb bowls with fuel.

    you could up the psi and flow rate of the pump to keep the header tank permanently full, and run a small diameter return line back to the tank to stop the fuel pressure overpowering the float bowl needles.

    But I would try what Spyda said first.

  5. #5
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    I was thinking about feeding from both ends of the header tank but with a 17 gallon per hour pump, was wondering why the header tank (a 2" x 6" tube) would have enough space to slosh the fuel away from the drain.

    I think I'll toss down a couple more pints and sleep on it.
    Ken: Suzuki '80 GS1100 Sidecar || Hack Nutz Racing (HackNutzR.US)

  6. #6
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    We ran one of those motors running GSXR1100 flat slides minus header tank and just used a Yamaha fuel pump off some carbed thing FZR400? maybe, It may of had one but I dont remember it having a return , it just slows down when it built up line pressure

    Originally we ran some kind of electric pump with a Holley fuel regulator and return which was ok but harder to set up, still didn't use a header tank with that either

  7. #7
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    Can you get inside the header tank? If you think it may be sloshing around you could try some fuel cell foam in there to act as a baffle?

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    Quote Originally Posted by Kickaha View Post
    We ran one of those motors running GSXR1100 flat slides minus header tank and just used a Yamaha fuel pump off some carbed thing FZR400? maybe, It may of had one but I dont remember it having a return , it just slows down when it built up line pressure

    Originally we ran some kind of electric pump with a Holley fuel regulator and return which was ok but harder to set up, still didn't use a header tank with that either
    Apparently you can run higher pressure pumps and regulator with the flatslides (that's what the ZX10 has), they supposedly hold back more fuel pressure than CV and CR carbs.

  9. #9
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    Quote Originally Posted by BASS-TREBLE View Post
    Can you get inside the header tank? If you think it may be sloshing around you could try some fuel cell foam in there to act as a baffle?
    It is 2"x6" (50mmx300mm). The end caps are welded on.

    It occurs to me that I haven't seen fuel running out of the overflow in a while. I'll check to see if it is clogged. Maybe air is getting trapped in the header.

    If not, I'll just remove it before the next practice and see what happens. Easy enough to reinstall.

    thanks for all the help guys!
    Ken: Suzuki '80 GS1100 Sidecar || Hack Nutz Racing (HackNutzR.US)

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    [QUOTE=nodrog;1130886878]Apparently you can run higher pressure pumps and regulator with the flatslides (that's what the ZX10 has), they supposedly hold back more fuel pressure than CV and CR carbs.[
    It's just stiffer springs in the float needles to put a pump on.

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    Quote Originally Posted by Kyler View Post
    It is 2"x6" (50mmx300mm). The end caps are welded on.

    It occurs to me that I haven't seen fuel running out of the overflow in a while. I'll check to see if it is clogged. Maybe air is getting trapped in the header.

    If not, I'll just remove it before the next practice and see what happens. Easy enough to reinstall.

    thanks for all the help guys!
    2x6 = 50 x 150??? where did you get 300?

    plastic fabricator/welder here if you need a hand ! will work for beer/bourbon/booze

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  12. #12
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    Quote Originally Posted by hayd3n View Post
    2x6 = 50 x 150??? where did you get 300?
    3rd pint?
    Ken: Suzuki '80 GS1100 Sidecar || Hack Nutz Racing (HackNutzR.US)

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    Only just seen this thread Ken.
    I've set up a lot of speedway cars on bike carbs as well as a couple of sidecars. I've always used a pump system with no header tank but a Hilborn idle bypass in the return line to the tank. from memory it's the second softest spring in the Hilborn kit which gives around 1.2psi at the float needles.
    Used with hoses at least 3/8in bore, and a good pump such as the facet you have, this is enough to run an 1100 on Methanol with no starvation issues.
    Just run a Tee before the carbs with the hilborn valve in the return line close to the junction.

    Your mid corner issues could well be surge in the float bowls too...Don't know what carbs you're using though.
    What I've done in the past to stop surge effects is to slip a piece of brass tube over the mainjet which is then trapped in place by the bowl. Cut slots in the bottom 1/2in of it to let fuel in and it keeps a supply of fuel available to the mains regardless of sideways G...
    Alternative to this is what George White did at my sugestion to the Mikuni 33's on his GSX1100 years ago and make mainjet carrier extensions which reached down into a deeper bowl nut...But the brass tube is easier.

    I really don't recommend going much over 1.2psi...Most carbs designed for gravity feed don't like more than this.
    To help me set up the numbers of speedway cars I was doing, I imported a 0 - 5 psi gauge from the US as nothing suitable was available here in NZ.

  14. #14
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    Quote Originally Posted by Grumph View Post
    Only just seen this thread Ken.
    I've set up a lot of speedway cars on bike carbs as well as a couple of sidecars. I've always used a pump system with no header tank but a Hilborn idle bypass in the return line to the tank. from memory it's the second softest spring in the Hilborn kit which gives around 1.2psi at the float needles.
    Used with hoses at least 3/8in bore, and a good pump such as the facet you have, this is enough to run an 1100 on Methanol with no starvation issues.
    Just run a Tee before the carbs with the hilborn valve in the return line close to the junction.

    Your mid corner issues could well be surge in the float bowls too...Don't know what carbs you're using though.
    What I've done in the past to stop surge effects is to slip a piece of brass tube over the mainjet which is then trapped in place by the bowl. Cut slots in the bottom 1/2in of it to let fuel in and it keeps a supply of fuel available to the mains regardless of sideways G...
    Alternative to this is what George White did at my sugestion to the Mikuni 33's on his GSX1100 years ago and make mainjet carrier extensions which reached down into a deeper bowl nut...But the brass tube is easier.

    I really don't recommend going much over 1.2psi...Most carbs designed for gravity feed don't like more than this.
    To help me set up the numbers of speedway cars I was doing, I imported a 0 - 5 psi gauge from the US as nothing suitable was available here in NZ.
    thanks! These are the stock CV carbs.
    Ken: Suzuki '80 GS1100 Sidecar || Hack Nutz Racing (HackNutzR.US)

  15. #15
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    meany meany years ago when I was raceing TQ midgets..
    I used the remote fuel bowl of a SU carb as a header tank..
    they have a inlet valve & float in them... In the end I cut
    the bottom off it & welded it to a 1 liter alloy tank as it
    did not quite have enough fuel volume...

    got it running great... then tossed it all away went to
    Hillborne injection ....








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