engine only runs when on reserve gas

Discussion in 'Engine, Fuel and Exhaust' started by slowboy, Mar 16, 2013.

  1. slowboy

    slowboy Member

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    was riding bike [ '95 HD Badboy ]...engine kept cutting off until I switched to reserve...then it ran fine...was told to check venting...could someone tell me how to do this, and if this is/might be problem?
    Thanks

    might need to add that 'both' tanks were full of gas...just filled them up before this started happening...
     
    Last edited: Mar 16, 2013
  2. Jeff Klarich

    Jeff Klarich Well-Known Member Contributor

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    Try starting the bike and removing or loosening the gas cap. If it's not venting properly it should run better if you try this. If it runs better you may very well have a venting issue.
     
  3. Breeze3at

    Breeze3at Well-Known Member

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    I THINK '95's had the vacuum operated petcock. The diaphragm is prone to fail, or the vac. line can crack and leak (esp. after this many years). If your petcock has 2 hoses (1 gas,1 vac.) running to it that may be the problem. If not, post back and we'll think of something else.
     
  4. glazier

    glazier Junior Member

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    One way to check the diaphragm is to remove it and install it backwards. That defeats the vacuum operation and makes it gravity fed instead. Its a simple check to see if that's the problem. If it is, then just replace the diaphragm or the entire petcock.
     
    1 person likes this.
  5. BUBBIE

    BUBBIE Well-Known Member

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    The way you describe the problem, I'm thinking the Upper side that delivers gas (on flow) may be obstructed inside the tank. When you switch the petcox valve to reserve and it works, means just that to me,,,, dirty in just that one opening. Turning the petcox by-pass to the regular gas flow Not enough gas and showing no problem on reserve.:s

    The FIX: remove gas from tank, remove the petcox and you will probably find debris in the taller pipe or hose that is the regular gas side.

    Some times you can take off just the turning mechanisum on the petcox and that will clean it out... Careful it will flow out when that turn flow valve is removed. getting it back in quickly may be a problem. :D Have a container handy and or lower tank fuel BEFORE any removal.


    I have been there and done this on my 95 sport and it WAS the problem stated above.

    signed....BUBBIE
     
  6. Breeze3at

    Breeze3at Well-Known Member

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    OR,,, You can remove the fuel line from petcock, slip another piece of line on and blow back into the tank, with air hose or other means of low pressure air, Not your mouth (that's my disclamer :bigsmiley17:).
     
    Last edited: Mar 16, 2013
  7. BUBBIE

    BUBBIE Well-Known Member

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    Make sure the gas cap is off when Blowing under pressure or you WILL hold a little bit more gas in that tank then planned.........:lolrolling

    signed....BUBBIE
     
  8. 89stroker

    89stroker Active Member

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    I say Bubbie has the answer, port blocked on the petcock, has happened to me before.
     
  9. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    It could be as simple as the petcock filter screen is blocked
    So just drain tank remove petcock and clean the filter screen and the fuel intakes

    Brian