Announcement

Collapse
No announcement yet.

Why carb leaking?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Why carb leaking?

    Hey guys, I've got an '89 ZX-7 that uses a fuel pump. Last night after my ride, I woke up this morning and found fuel leaked into the #2 intake tract filling it completely up. I'm trying to understand how this can happen on a bike with a fuel pump. I mean, even if the needle valve was blocked open by something, how would fuel continue to get in there? Thanks for the help.
    1982 GS550M Rebuilt Winter '12 - 550 to 673cc engine conversion.
    1989 Kawasaki ZX-7 Ninja
    2016 Ducati Scrambler Full Throttle

    #2
    Can you post some information about the fuel supply system? Could be the pump isn't needed until the fuel drops below some certain level in the tank. Or there is some diaphragm failure, in the petcock for example, which allows fuel to backflow into the engine. Might be a good idea to check all the possible failure points.
    Ed

    To measure is to know.

    Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

    Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

    Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

    KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

    Comment


      #3
      Sure Ed,

      As far as I know, the fule pump runs all the time. Petcock is a non-vacuum type. The pump sits below the level of the carbs. It appears to be pumping fine. I have not checked it yet to see if fuel is flowing through it without power. However, I figure if the pump is letting fuel flow all the time more than just the #2 carb would over flow no? I'll check the pump for non-powered flow tonight.
      1982 GS550M Rebuilt Winter '12 - 550 to 673cc engine conversion.
      1989 Kawasaki ZX-7 Ninja
      2016 Ducati Scrambler Full Throttle

      Comment


        #4
        See if there is a check valve in the pump that prevents flow unless it's actually pumping.

        .
        sigpic
        mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
        hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
        #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
        #2 son: 1980 GS1000G
        Family Portrait
        Siblings and Spouses
        Mom's first ride
        Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
        (Click on my username in the upper-left corner for e-mail info.)

        Comment


          #5
          Ok, the pump is bad. It's flowing fuel without power. I just replaced that thing 3 months ago. Probably made in China...
          1982 GS550M Rebuilt Winter '12 - 550 to 673cc engine conversion.
          1989 Kawasaki ZX-7 Ninja
          2016 Ducati Scrambler Full Throttle

          Comment


            #6
            some bikes have fuel pumps that aren't needed at all, until you run down to the last 1/4 tank, then gravity needs a little help to maintain flow rate into bowls.
            Is tank full? That's why it's flowing even with power... gravity is taking over. As usual, Steve is on top of it :-)
            1980 GS1000G - The Beast - GOING... GOING... yup, it's gone. I'm bikeless !!! GAaaahh !!!
            1978 KZ1000C1 Police - GONE !
            1983 GPZ750, aka ZX750A1 - restored, fresh paint... Gave it back, it was a loaner !!!
            Check My Albums for some of the 30+ headaches I've dealt with

            I know -JUST- enough to make me REALLY dangerous !


            Comment

            Working...
            X