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carbs still leaking

Discussion in 'XJ Technical Chat' started by lopezfr2, Oct 22, 2009.

  1. lopezfr2

    lopezfr2 Member

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    so i put a whole new set of float bowl gaskets on the carbs, and they're still leaking. theyre actually leaking worse then they were before. i dont want to register the bike until i get this sorted out so i need to figure out why this is happening. i don't know enough about carbs to use specific names but if somebody can explain in dumbed down terms how to tear them down far enough to get to where there might be some failing o-rings.
     
  2. JFStewart

    JFStewart Member

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    It sounds like the needle valves are leaking. When you had the bowls off did you make sure that they were free, clean, and adjusted correctly? The gaskets really don't hold pressure, they just stop splash from escaping. I would suggest that you go through the entire cleaning, and adjusting process. Chacal has manuals that are easy to follow. There have been several posts on this topic.
     
  3. lopezfr2

    lopezfr2 Member

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    i read over rick massey's carb cleaning guide but never having seen inside them before it was all pretty much meaningless to me. now that ive been inside the bowls it all makes pretty good sense. what exactly should i look for on the needle valves to make sure they are in good shape? what can i do to make sure they are adjusted correctly or set them so they are? while im in there is there anything else i should look for that might be causing this leaking? like i said the leaking comes from the float bowl gasket
     
  4. wizard

    wizard Active Member

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    Have you got the carbs off the bike?
     
  5. lopezfr2

    lopezfr2 Member

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    im at school right now but ill have them off as soon as i get home.
     
  6. adrian1

    adrian1 Active Member

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    ?? RU sure they are leaking from the gasket area as this would be unusual. RU sure they are not leaking from in between the carbs therefore indicating failed o rings. BTW don't overtigthen the screws that hold the bowls on in an attempt to fix a suspected leak.
     
  7. lopezfr2

    lopezfr2 Member

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    yes im very sure its leaking from the gasket area, when i wipe the side of the float bowl off i can see the fresh stream come out of the top of the bowl
     
  8. Broke_Dirty_Maxim

    Broke_Dirty_Maxim Member

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    Did you clean all of the old gasket, and any varnish from the mating surface before you put the new gaskets on? It only takes the smallest amount of contamination or old pieces of gasket to break the seal.

    Gaskets or seals don't just simply magically prevent leaks just because they are gaskets and seals. They also require clean mating surfaces in order to perform properly.
     
  9. lopezfr2

    lopezfr2 Member

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    yes they were cleaned when i put the new gaskets in, and it was leaking the same way before i put the new gaskets on
     
  10. Broke_Dirty_Maxim

    Broke_Dirty_Maxim Member

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    Can you post pictures of what you are talking about?
     
  11. lopezfr2

    lopezfr2 Member

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    ok here are some pictures that can possibly help out. in the first picture i can see theres a small amount of gas on the outside of the carb bodies, but it doesnt get any higher than the top of the circled area, and its only on the back side of the carbs. in the second picture, the line is along the float bowl gasket where i can see gas leaking out of while the bike is running. in the third picture the plastic joint where the fuel line comes in is cracked on either side where the red lines are, but i dont think its leaking since its dry. i can hit it with some rtv if i need to. if the bike isnt running the leak is very slow, if i leave it over night there will only be a small puddle of gas in the pan under the first carb right under the drain screw. but if the bike is running the leaking gets worse and i have to dab the excess gas from the spot where the puddle forms with a rag to keep it from splashing around. i hope this can help somebody help me figure out whats going on
     

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  12. Broke_Dirty_Maxim

    Broke_Dirty_Maxim Member

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    I think your transfer tube or tubes are leaking. Especially if you are referring to the fuel pooling up where you are showing with the bike on the sidestand.

    If you can confirm that it is the transfer tubes, I would replace the center t-fitting as well as all the packings on all of the tubes. There are two transfer tubes and each one has two packings on each side, and the t-fitting does not have packings as it has rubber rings that act as seals.

    Oy yeah, you have to split the carbs apart to perform that repair. But if it makes you feel any better, they lasted this long so you will never have to change them again.
     
  13. lopezfr2

    lopezfr2 Member

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    how can i confirm what parts are actually leaking? i dont want to have to break the whole rack down and find out the problem was something simpler
     
  14. Broke_Dirty_Maxim

    Broke_Dirty_Maxim Member

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    Honestly, I don't know how to answer your question except to say look closely.

    Put the bike on the centerstand so the fuel isn't running down to the left side and get a good flashlight and a small mirror so you can see between the carbs.
     
  15. lopezfr2

    lopezfr2 Member

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    i was afraid of that. well as long as the carbs are off the bike ill check out the needle valves and after that i guess we'll have to wait and see til i get them back on. as luck would have it i just got this little round mirror thats attached to a telescoping rod for looking at stuff in hard to reach places, best $2 ever
     
  16. Broke_Dirty_Maxim

    Broke_Dirty_Maxim Member

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    Dude. If the carbs are still off the bike, get a length of hose and hook the tank up to the carbs with the petcock set to the prime position. Keep the carbs somewhat level and start checking for the leaks. You won't even need a mirror now. Make sure the carbs are still assembled or you are just going to make a big mess of fuel.
     
  17. lopezfr2

    lopezfr2 Member

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    couldnt i just do the same thing with water? like if i attach a piece of fuel line to the inline filter and use a funnel to pour water into it, or will that leave mineral deposits that will mess with the carbs, or would that damage the carbs? i just dont want to get fuel everywhere. sorry im a n00b when it comes to carbeurators
     
  18. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    no. Water (or windshield washer fluid, an oft-recommended alternative) has a different specific gravity (fluid density/bouyancy) than gasoline. If you use water or a water-based fluid you won't get the float levels right. You could use mineral spirits but that's nearly as flammable anyway.

    It doesn't take much to set up a fuel-based leveling rig; you can use an empty bottle for a fuel tank (I "borrow" the fuel tank off my son's minibike.)
     
  19. wingnut325

    wingnut325 Member

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    For a cheep easy test tank for fuel try the gas can that you would use for your mower ect. You can see I even use it for test rides and tuning. Just hook a fuel line up to the plastic tanks vent fitting

    [​IMG]
     
  20. lopezfr2

    lopezfr2 Member

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    i havent gotten a chance to find out where the leak is yet, but i have another stupid question. do i have to disassemble the lower carbs before i can take off the hats and do the clunk test? or i can i do it with the rest of the carbs together?
     

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