Carby Throttle not moving. Float adjustment? / s.c. m.b. bike laws

Discussion in '2-Stroke Engines' started by lucky13, Aug 20, 2009.

  1. lucky13

    lucky13 New Member

    So I looked down in the carb, and the float is off center.

    Does the float adjust when the pin goes in, or do i need to take off carb and adjust?

    Can any of you send me links showing how this is done if need be?

    Off subject, South Carolina motorized bike laws are a joke.
    They seem to just work in circles. Legal/illegal. Aggravation.

    If anyone can also send some actual information on if they are legal..

    Are they considered a motor assisted bicycle, moped...etc.

    Do you have to have a valid drivers license, or moped license...
    Do you have to have a license at all?

    Ive been all over the s.c. dmv website, and other local legislative websites..
    i just can't find a definite answer.

  2. motorpsycho

    motorpsycho Active Member

    you can not see the float by looking down the carb. the only way to see the float is to remove the float bowl on the bottom of the carb.
    to adjust the float, you have to gently bend (up or down) the 2 prongs that open and close the needle & seat.
    bend them up to let more fuel into the float bowl, bend the down to let less fuel into the float bowl. this can be trial and error and if you bend them down too much, sometimes it won't allow enough fuel into the bowl, and the engine will die because it'll run out of fuel (the fuel that's in the bowl.)
  3. lucky13

    lucky13 New Member

    oh, ok.

    so what is the name of the part that the pin fits into?
    bc whatever that part is, is off center.

    does it adjust on its own? or do i need to do this?

    im still trying to find where the resistance is coming from.
  4. motorpsycho

    motorpsycho Active Member

    are you talking about the pin that's in the carb slide? it's a long tapered pin that moves up & down with the slide when you use the throttle. if that's the part you are referring to, it's called the jet needle. (the pin) it goes up & down with the slide, and it fits into the needle jet (the hole in the bottom of the carb. while looking down at it from the top with the top off.) the hole that the jet needle (or pin) goes in and out of is called the needle jet. (if that's what you are saying is off center.)

    if you're talking about the pin that is cast into the side of the carb body (on the inside) that a slot in the slide lines up with...i have no idea what that pin is called.
    if you are talking about that pin (it's very small) i don't think it's actually centered in the carb.
    if you are talking about the needle jet hole, it should be centered so the jet needle will move up & down with out rubbing or binding on the main jet hole. the jet needle will naturally be perfectly centered as it hangs from the carb slide, but you will be able to move it around because it is held to the carb slide with a small "c" clip. but if the needle jet hole is off center, the jet needle may be rubbing on the side of the needle jet hole as it goes up & down. but in reality, that should not cause enough friction for it to bind because the jet needle has a loose fit in the carb slide. unless the needle jet hole is so far off center that the jet needle is actually missing the hole as the carb. slide goes down. but the jet needle never comes all the way out of the needle jet hole once the slide is all the way in the carb.
    i'd like to see pics of what you are looking so i know exactly what pin you're talking about.
    i think we are on the same page, but i'm not sure yet.
    here's a generic carb. cutaway picture.
  5. lucky13

    lucky13 New Member

    thank you for being patient with me.

    yeah, the jet needle hole is off centered.

    i took a long skinny nail and put it in the needle hole to see if it would adjust on its own.
    it did.
    not the result i was looking for.

    i would have settled with taking the carb off and fixing a problem, over not knowing what is wrong.

    so i took the assembly out of the carb, and rotated the throttle making sure the cable wasnt pinched, bent..etc.
    no problem.

    then i carefully put the needle in the hole while guiding the assembly correctly on the carb slide pin. i easily pushed it down. then i tried to ease it out, but its still sticking.

    i remembered something i read here about the carb slide getting warped from using pliers.
    i had better sense to use pliers anyways, but i still checked to see if the carb slide was warped.... nope. it wouldn't be that easy for me.

    what should i do now?

    something found interesting was as i rotated the throttle i watched the needle assembly
    (outside of the carb slide) pull in and out. i noticed the needle pulling sideways as it tightened, due to the cable being routed a little off center in the housing that the pin and washer rests in. what is the name of that piece?
    would this pulling somewhat sideways affect how smooth it guides?
  6. motorpsycho

    motorpsycho Active Member

    the needle pulling sideways might affect it because as the needle goes down into the jet needle, the hole gets smaller (this is where the carb gets it's fuel that goes into the engine. as you give it throttle, the needle raises and vaccuum pulls fuel from the float bowl, through the jet, up into the carb and then into the engine). the needle may be binding on the smaller inside part of the needle jet.
    when you rotate the throttle, and the slide and needle move up & down, the needle should stay somewhat straight. if it is being pulled at an angle, the cable may be interferring with the needle as it's raised.
    the part that the cable goes into (the slot on the side of the slide) really doesn't have a name....just the carb slide.
    by putting a nail into the needle jet and somethign moved to be more in line, that tells me that the jet itself may not be screwed in all the way or loose. the jet is threaded (on most carbs. anyway) and if it's loose or not screwed in, it will move around...the result is that your motor proabbly will run like **** and be really rich.
    i think (ot sure on these carbs.) that you can remove the float bowl, turn the carb upside down and access the jet through the bottom. the jet shoudl have a slot in it that you can use a regular screwdriver on to tighten it back in. it will only be in one position once it's tight. the jet does not have any's either screwed in or not screwed in. (i'm hopin gthat this is what you are looing at).
    i have read that in some of these carbs (on the japanese engines) that the jet will either back out and loosen because it was never tightened when the carb was assembled, or it will back out on it's own after running.
    i hope this helps you.
  7. lucky13

    lucky13 New Member


    Thanks again for your help. You've been awesome.

    so i somehow "fixed" the problem.

    i just pulled the assembly out and slid it in and out until it was gliding smoothly.

    it was a great feeling to finish(for the main part), and go for a ride.
    i was sure not to be hard on it. i cruised along.. i did pick some speed up...
    but I would like to break the motor in right

    but i did find out that i could have been arrested for using this on s.c. roads!
    turns out that here you have to register it as a moped.. and follow ALL of the moped laws.

    The only thing though... its seems impossible to register a MB as a moped.

    oooo.... these guys are tricky.
  8. motorpsycho

    motorpsycho Active Member

    no problem.