Fuel Bowl Runs Dry and Dies.

Discussion in 'Engine, Fuel and Exhaust' started by Bsporty, Jan 29, 2010.

  1. Bsporty

    Bsporty Member

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    got a 72 sporty that seems to run the fuel bowel dry after giving it the gas and then letting off the throttle it dies. Let it sit for 1/2 a minute it will start again, and then do the same. just put on a cv carb from a 883 i think. Replaced the42 slow jet to a 45 and the 165 main to 175, shimmer the needle with 2 #4 washers. plugged the vacuum line at the top of the carb. Turned the idle mixture out 2 1/2 turns. Could it be my float or float level? Have not touched it. Well I took it off to clean and blow out.
     
  2. Chopper

    Chopper Senior Member

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    Re: Fuel Bowel Runs Dry and Dies.

    Welcome to the forum, I would check everything else before messing with the float adj.
    On a 72 the things I would check is the fuel cap first, it needs to be vented, you can tell by cracking it open while running when it wants to die, just be carful and don't have a full tank. The other thing is the fuel screen in the tank, they have a tendency to get restricted with rust on a bike that old, most people I know also run a inline fuel filter. Congrats on the CV carb, you picked the best street carb made, hope it's 90 or later with the pumper in it. Good luck
     
  3. NEWHD74FAN

    NEWHD74FAN Experienced Member Retired Moderators

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    Re: Fuel Bowel Runs Dry and Dies.

    As Chopper says, make sure there are no restrictions upstream from the carb. You can check the fuel level in the float bowl without disassembly or "fiddling" with the float/needle assembl; at least before using a clear tube inserted into the threaded hole of fuel bowl drain plug to check float level is with 1/8" of the seam near the top. Again before changing a whole bunch of stuff, you should do non invasive checking of stuff first to have a good starting point, rather than jumping in the middle and possibly compounding problems.
     
  4. glider

    glider Veteran Member

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    Before suspecting the carb, make sure there is adequate fuel flow from the tank through the lines to the carb. There may be something in the fuel strainer in the tank blocking the flow up. Also possible the float is just hung up. Try tapping the carb with the handle of a screwdriver and try it again.
     
  5. silentflyer

    silentflyer Active Member

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    Good, he's Back!!! at least part time!!!
     
  6. Bsporty

    Bsporty Member

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    First I want to thank all you guys for quick responses, can’t tell you how grateful I am.” Chopper” I do have a inline filter that seems to stay full when it dies out, will check tank screen. May still be restricted enough to stall out. Had the tank off about 12 years ago for repairs (re weld seam) and relined so not in the tank. “Glider” will try tapping on fuel bowel. “Newhd74fan” I’m in Canyon Country. Will get to all this today and report back later






    [note]
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    Last edited by a moderator: Jan 31, 2010
  7. Bsporty

    Bsporty Member

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    Took the petcock out cleaned the screen, replaced the inline fuel filter and fuel line. Ran the bike when it started to die I opened up the gas cap, but still died. Tomorrow will try setting the float level. Got instructions from a Glider post. If that fails I’ll take “Choppers” advice and try hollow points on her.
     
  8. Chopper

    Chopper Senior Member

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    Woe, we haven't even got a catholic priest to perform a exorcism yet, don't give up so easily, you'll get it. Do you have a Accelerator pump on the carb? If so take the air cleaner off & check the spray, if it's working when it's trying to die, if so you have a bowl full of fuel. Is the vacuum piston rising when you give it throttle? Is your Enrichener on or off when it dies? When you pull the float bowl off try turning on the fuel valve with something to catch the gas in and see if the fuel flow is steady or if it stops. When you let it just idle does it die or only when you give it throttle? Let me know, also sometimes electrical problems can appear as fuel problems. Just keep thinking how good it's going feel when you fix it:)
     
  9. Bsporty

    Bsporty Member

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    Chopper got a long history of carb problems 25 years. The last carb a Andrews Flow Master wasn’t any better. Did I mention I have XLCH the CH means you got to kick. That why it’s spent more time collecting dust than bugs. I know! I just want to answer a few of your much appreciated questions. I do have a accelerator pump. The vacuum piston does rise when given throttle. She does idle when warmed up. The enrichner is off when she dies. I haven’t run the bike without the air cleaner yet to see if it still spray fuel when it dies but I can tell you that when it dies twisting the throttle doesn’t revive her. That’s why I think it must be drying up. Today I will take the bowl off to make sure fuel flows. I will also check the float level I believe it should be 15mm via Factory Pro Float Height Tool. Your rights about the electrical problems haven’t gone there yet. Thanks again. report later.
     
  10. Chopper

    Chopper Senior Member

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    While the air cleaner is off put your finger in the throat and push the piston up, should be more then just spring tension, you should feel the chamber pressure if there are no leaks. I would also double check that the needle feels right while your in the carb.