carb adjustment?

Discussion in 'Motorized Bicycle General Discussion' started by Dougan, Aug 26, 2010.

  1. Dougan

    Dougan New Member

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    I just replaced m yspark plug and changed from 25:1 and 32:1. My bike rides like it's choked a little bit and won't get above 22 or so (maxes around 30). I took the intake filter off and it rides beautifully without the filter. Cleaned it, put it back on, rides like it's choked.

    I know little about carbs. But it sounds like I need to open it up and adjust the needle or float or whatever that is. Does anybody have a tutorial for something like this? Sounds common and I couldn't find one.

    Unless you think there's a different problem.
     
  2. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Move the C clip on the needle up a notch or two, & post back how that worked.
     
  3. Dougan

    Dougan New Member

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    Does anybody have a picture of this?
     
  4. ferball

    ferball New Member

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    Don't be afraid of taking the carb apart, that stock carb is one of the simplest carbs I a have ever torn into, the only "tricky" bit is the pin for the float valve, it wants to fall out, but that is the worst of it, tear it open it is kinda fun...
     
  5. Dougan

    Dougan New Member

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    Okay, thanks for the tips.

    I took it apart. Was set to #2 from top. I moved it to #1. I'm fairly certain that this helped a little-- not sure if I am just making it up, or if it actually helped. But either way, it didn't help enough. The bike is acting like it's a little choked, and won't make it to its normal max RPMs with the air filter on.

    I tried moving it to #3 from the top just to see, and this seemed to make it worse just a little.

    Checked for air leaks, none. Tried messing with the cable at the top of the carb, no effect.

    Spark plug is L86J, 32:1 amsoil dominator synthetic. The carb I've got is the one with the red intake. Ive seen a efw pictures of it around here.

    Weird thing is, if I am at even the slightest downhill grade, it seems to help and I'm able to get up to about my normal max speed. It seems like it runs just a little better after about 1 mile of riding, when it's fully warmed up.

    Any other tips?
     
  6. GearNut

    GearNut Active Member

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    How many miles are on the engine?
    What is the float height set at? Spec is 21mm from gasket surface to top of float (actually the bottom of the float as this is measured with the carb up-side-down.
     
  7. Dougan

    Dougan New Member

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    The engine has about five gallons of gas run through it. I don't keep track of miles. But I'd have to guess 500-750 miles.

    I don't know about the float. To be honest, I've never rebuilt a carburetor and don't know how to identify it. I thought that the needle and the float were kind of the same thing. Could you give me some guidance toward how to figure out the answer to your question?

    Thanks!
     
  8. NunyaBidness

    NunyaBidness Active Member

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    #9 NunyaBidness, Aug 27, 2010
    Last edited: Aug 27, 2010
  9. Dougan

    Dougan New Member

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  10. Dougan

    Dougan New Member

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    Okay, I'm out of ideas. I've changed back to my previous spark plug, adjusted the carb needle to every level, and even switched my oil mix back in case that was messing with my fuel:air mixture. Nothing has even had a noticeable effect. Even switching the carb needle from top to bottom does not havea noticeable effect. The only thing that I do that has an effect is when I take the air filter off completely, it gets noticeably better, but not completely fixed.

    Sometimes at WOT it will go for seconds without ever firing once. It's like the killswitch is being pressed. But I doubt CDI part of the engine has any blame since the removal of the air filter helps.

    Does anybody else have any ideas? I'm stumped here.
     
  11. GearNut

    GearNut Active Member

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    What is the float height adjusted to?
    If it is too low it will cause what you are describing.
     
  12. Upper Class White Trash

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    well only guess i can give is if you haven't replaced the cap for your plug it may be to blame.

    mine at high revs seemed to be starving for fuel but all checked out there.
    the clip in the cap broke and the cap was dancing around on top of the plug.
    fixed it and starving feel went away.

    it may be feeling dead for a few cycles because plug and cap loose contact.

    hope you figure this out!!!
     
  13. insomniacshotrods

    insomniacshotrods New Member

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    I cut open my stock airfilter so i looked like a frown face, but a straight shot of air was able to come in. Are you running a light off the white wire from magneto? If using to much wattage of a light you will effect spark and in some cases will not allow motor to even start..ask me how i know lol..open up air cleaner, put on number 2 setting or 3, open up exhaust and cut off the end tube inside about 1/4 inch from end and use ngk bh5 spark plug, and get a different coil wire. They just screw in. Make sure your old ones are on tight also till you replace.
     

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