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Petcock

Discussion in 'Motorcycle Tech Talk' started by boyd, Jan 9, 2008.

  1. boyd

    boyd New Member

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    i am having problems that when i try to drain the gas tank the gas just
    kind of dribbles out,could this be a bad petcock.
    i have already pulled it to check if it was plugged and it wasnt.:) :)
  2. ringo912

    ringo912 Active Member

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    What bike do you have?
  3. hotroadking

    hotroadking Super Moderator Staff Member

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    A stock HD petcock is vacumn operated, unless it's got a vac pull going on from the intake it's not going to drain anything, did you put it on reserve?

    Usually that will work to drain the tank.

    I replaced mine with a Pingle High Flow petcock, non vac operated.
  4. boyd

    boyd New Member

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    i have a 1974 shovel with fatbob tanks
  5. chucktx

    chucktx Moderator Staff Member

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    two things....pull the caps, one is supposed to be vented, and if it is clogged it will not drain,,,,,the petcock is plugged or the valve is not turning all the way due to being broken or clogged itself......if you pull the petcock and the gas comes out really fast, then the problem is in the petcock....if it is still slow, then someone may have sealed the tank improperly and has the hole covered.....let us know what ya find!!:)
  6. chucktx

    chucktx Moderator Staff Member

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    sidebar..........the right side cap should be the vented one....there is a cross over between the tanks under the dash.....it may be clogged or non existant.....:)
  7. boyd

    boyd New Member

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    i will check those ideas to see if they may be the problem.
    but for now i would like to say thanks for your input.
    BOYD
  8. chucktx

    chucktx Moderator Staff Member

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    anytime...that is why we are here, to help and have fun!!!..:)
  9. hotroadking

    hotroadking Super Moderator Staff Member

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    ok best bet is to open the gas cap in case the vented cap is stuck it won't drain probably wouldnt' run worth a crap either.

    Then pull and check that petcock, could need a new filter/screen they pick up a lot of futz over time.
  10. cowboy

    cowboy Moderator Staff Member

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    boud you said you pulled it , did you chace it with air ? if so air will go through faster then the gas will , & like said above pull the caps & & see if it drans faster , Has your bike been setting up for any lengh of time ? might just be all gummed up inside the valve part
  11. boyd

    boyd New Member

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    I took both caps off and thier was no differnce inthe flow of gas,And it would run all day at an idle,but if i went down the road 3 or4 miles it would run like
    crap like it was starving for fuel.Could it be that it is not letting enough fuel through to keep the floatbowl full.
    THANKS
    BOYD
  12. chucktx

    chucktx Moderator Staff Member

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    boyd, that is exactly what is happening. lets start with the basics...pull the line from the carb and turn on the fuel. are you getting a good flow? then work backwards twards the tank. removing every connection to check for flow. once you get to the tank, remove the petcock, check for no obstructions. i have seen gas lines get clogged with the inner rubber. it gets peeled when pushing onto a fitting. the inner line gets cut then forms a flap to prevent flow. doing these steps you will have to find out where the problem is. if the flow is good all the way to the carb, then you need to remove the bowl and check in there. dirt at the float seat, a float that wont float....(full of gas)....float not set correctly.
  13. cowboy

    cowboy Moderator Staff Member

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    Now it 's starting to sound more like dirt in the carb , how long has you bike set-up with out running , might be if it sat it's gummed up the carb , or are the fule lines to close to the heads might be a vapor lock aka hot gas , or a fule line colapseing (sp)
  14. boyd

    boyd New Member

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    MyBike has set for 2years. The problem right now is Ihave it striped down for repainting and I am rewiring it while I have it apart I live in Michigan so the weather right now sucks. So when Iput it back togeather hopefully these great suggestions will steer me down the right path.
    AGAIN THANKS
    BOYD
  15. ringo912

    ringo912 Active Member

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    Hey Boyd...where abouts in Michigan are you?
  16. hotroadking

    hotroadking Super Moderator Staff Member

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    OK with that info, do as chuck said pull the fuel line turn it on reserve and check flow.

    Also pull the carb off and take off the float bowl, clean it out, and remove and clean the jets check for futz in the jets, thats the stuff that forms over two years of sitting around

    A little compressed air from your compressor or you can get one of the compressed air cans for pc cleaning and use it .

    Also open the top of the carb if its a cv and check the diaphram make sure it's not broken or cut be careful when you reinstall not to cut or pinch it.
  17. boyd

    boyd New Member

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    I live in HUDSONVILLE A SUBURB OF GRAND RAPIDS.
  18. cowboy

    cowboy Moderator Staff Member

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    i thought it sounded like a gummed up carb , do as hot RK said & it should be fine

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