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Fuel overflow

Discussion in 'XJ Technical Chat' started by Harvey Thomas, Jul 4, 2020.

  1. Harvey Thomas

    Harvey Thomas New Member

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    Hi guys,

    Recently acquired an xj550 and having some carb issues. At first the bike wouldn't start, drained out old fuel and filled with new. Managed to get it started idling badly and cutting out.

    Decided to give carbs a good clean, so cleaned up, replaced fuel filter also.

    Put back in bike and low and behold ive made it worse, fuel is spilling into the airbox!

    Carbs out once more, notice butterfly valves slightly open, adjust and correct, get slides moving as they should this time, adjust each carb to 2-1/2 to 3 turns.

    Before I put in I put carbs level and run fuel in the top....fuel spilling out through the air side.....

    Now strange thing is that this wasn't happening to begin with???

    I'm assuming a rebuild with close attention to the floats? Based in Bristol UK, anyone know the best place to buy the stuff? 20200703_150907.jpg
     
  2. bensalf

    bensalf Well-Known Member

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    if its just overflowing , and it wasn't before, then float adjustment is needed, clean the float needles ,and the float seats with cotton buds ,with some solvol autosol , or "peek" any metal cleaning agent will do , just make sure you clean it all off after. then adjust static float height as per spec. all above will cost you nothing. after that , then look towards replacing float valves. try Yambitz or Wemoto for spares , if not N.R.P , carburettor spares may have what you need
     
  3. Harvey Thomas

    Harvey Thomas New Member

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    Thanks mate, I'll clean out the float valves tomorrow and give it another shot!
     
  4. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Or you you have a float stuck open, or you have a fuel valve needle tip that has hardened up and isn’t selling anymore....personally, I’d do a total teardown, cleaning, and rebuild.
    Do it once and be done, or take it apart a gazillion times chasing your tail
     
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  5. JCH

    JCH Active Member

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    Make sure that your not leaving your fuel petcock on prime,i just leave mine on reserve all the time to prevent any issues with turning it the wrong way or worst yet that is not leaking flowing into the carbs when the engine is turned off with no vacuum on the line to the valve,i realize that the needle and seat should stop the flow but isn't always the case,pressure can also cause issues.But in your case sounds like a needle and seat issue.
     
    Last edited: Jul 6, 2020
  6. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Not the best idea.....

    1. Even on PRI, you should not have fuel issues. If you do, you have a leaky fuel valve issue.

    2. RES is there for a reason. If you leave it there all the time, you better pay real close attention to mileage..... if it starts to stumble cuz you’re “out of gas”, you’re really out of gas and you have no reserve. That’s what you switch to reserve for....the only difference between RUN and RES is the levels of the screens on the petcock tower. Time to phone a friend or hope you’re on top of a hill with a gas Station close enough to coast into.
     
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  7. Harvey Thomas

    Harvey Thomas New Member

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    To clarify

    I taken apart once more, taken float valves out and cleaned, found grit under one hoping this was the issue put back together.

    Hooked up the tank, turned to PRI.

    Fuel fills and doesnt stop, comes out of 1 and 4.

    Am I missing something or shall I just order new float valves?
     

    Attached Files:

  8. a100man

    a100man Well-Known Member

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    It'll be the o-rings on the brass needle valve 'holder' letting by.. they are an odd size I think imperial but 7.5 x 1.5 mm fit well enough to work.
     
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  9. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Or the floats are are sticking open, or the rubber tips are shot.....but yes, the only way fuel gets into the bowl is through the valve.

    personally, I’d recommend replacing all 4 valves. I replace them automatically as a standard part of every rebuild
     
  10. Harvey Thomas

    Harvey Thomas New Member

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    Do you know where to source the parts in the UK? There are some on ebay from Taiwan....any good?
     
  11. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    I do not trust any parts from ebay.

    contact LEN at: info@xj4ever.com

    he’ll set you up with what you need. He does ship internationally.

    dave Fox
     
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  12. a100man

    a100man Well-Known Member

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    Dave is the carb expert and Len is the parts guru and only sells the best, but you can see how 'flat' that o-ring is in your picture, I'll bet those holders almost fell out.
    How far you go with the carbs depend on your budget and your long term use expectancy.
     
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  13. bensalf

    bensalf Well-Known Member

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    for carb parts in uk ,try N.R.P. carb parts , they should have what you need
    stu
     
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  14. Harvey Thomas

    Harvey Thomas New Member

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    Right ok, got the parts I needed working on putting them in today. But don't know where a couple go..heres a pic 20200708_142714.jpg
     
  15. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Those are from generic parts kits. I don’t buy those. I get my carb kits exclusively from Len.... that way I know I got the right kits and parts to begin with.

    that being said, to the question posed,
    -the big o-ring looks like a bowl drain screw o-ring
    -the small o-ring is for a mixture screw
    -the aluminum plug is for capping the the mixture screw well.

    Dave F
     
  16. Harvey Thomas

    Harvey Thomas New Member

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    Are you saying they don't go anywhere? I got thses from yambits. I cant really wait for overseas shipping etc
     
  17. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Read the rest of previous reply.

    when you put the mixture screw o-ring on, don’t forget to check the washer and spring——
     
  18. Harvey Thomas

    Harvey Thomas New Member

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    Duh, sorry Dave!!!! Thanks very much
     
  19. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Lol—np
     
  20. Harvey Thomas

    Harvey Thomas New Member

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    So the plot thickens! Rebuilt and cleaned the carbs and started on the button. Came to sync it all up this morning and no start!! Turning over but not catching! Ideas?
     

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