1st build/1st ride - carb ????

Discussion in '2-Stroke Engines' started by oldguy387, Apr 26, 2011.

  1. oldguy387

    oldguy387 Member

    Took my first build on its shake down ride. Didn't go far, just wanted to see how it ran. It ran fine except when the ride was over. Engine raced when clutch was pulled. Now, on the adjusting screw do I turn it out to allow the slide to go further into the chamber cutting off air or do I turn it in? Thanks Pic was taken during build.

    Attached Files:

  2. spad4me

    spad4me Member

    Remove the air filter and look down the carburetor throat.
    Is the choke partially open or fully open. Remember the position of the small lever that controls it.
    Use a flashlight if necessary.
    Twist the throtte back and forth.
    Does the slide move all the way up and down or just stay put in one place.

    There is a pin in the side of the carb and a slot on the side of the slide. they must be aligned for proper operation.
    Also the carburetor is so cheaply made that even if it is aligned the slide is round, and the carburetor body may be egg shaped.

    Slightly loosen the entire screw top of the carb to fix this LOL.
    The following is slightly expensive if you are wrong. If you can tell where the bulge in the carb body is pinch it with a big pair of pliers or vicegrips. broken carb is about $30.00.LOL

    The screw on the side of the carb is a joke use the cable end adjustment on top of the carb , to adjust the idle unless you have allready tightened the screw all the way in. If so loosen it .
    Last edited: Apr 26, 2011
  3. motorpsycho

    motorpsycho Active Member

    sounds to me like your idle is set too high. turn the idle screw out to lower the idle, turn it in to raise the idle.
  4. oldguy387

    oldguy387 Member

    Thanks for the info - First off my choke was so loose it could be moved by the wind. I tightened that up so that now you need two hands to move it and it made a world of difference. That helped the idle allot. Now I am just fine tuning. It is fun to ride again. Thanks Dale
  5. Ozi

    Ozi Member

    hiya 387, I like your simple method of the elbow for the carb to clear the frame. How are you clamping the elbow to the manifold using the hose clamp? manifold is pretty rigid.. whats goin on there?

    Attached Files:

  6. goodtime65

    goodtime65 Member

    This set up is not going to hold up you need way more clamping power
  7. adrian101

    adrian101 Member

    Beautiful looking bike. I had the same problem with my nt carb, I took it apart and put it back together. after that it worked perfect. I didn't know what i done, but whatever i did i worked magic. lol maybe it will work for you too.
  8. oldguy387

    oldguy387 Member

    I used hose clamps. This may be a temp fix as goodtime said, but for now it is holding. You have to tighten the clamps with a ratchet, not a screw driver. From the intake, I cut four slits in it where the elbow hooked up for better grip. We will see how this works. Right now I am riding and still working on fine tuning the carb. It seems to me that carbs are a real pain in the rear. Does anyone make a really GOOD carb?
  9. DuctTapedGoat

    DuctTapedGoat Active Member

    Dellorto makes good carbs - if you can find an NT Speed carb, that'll be a good upgrade too.
  10. motorpsycho

    motorpsycho Active Member

    with that set up, i'm wouldn't be surprised if you have an air leak.
    an air leak would explain your high idle problem, and it will make the engine run REALLy lean, which will burn up the piston.
  11. oldguy387

    oldguy387 Member

    the carb.set up

    I am going to change this set up this week end. I have a spare carb and an intake. I am going to Home Depot this am. to get another elbow and some different clamps. I am then going to put it together and maybe use JB weld or something similar to plug any air leaks. I just think my problem was my choke as the idle is pretty good right now. Thanks.
  12. motorpsycho

    motorpsycho Active Member

    i would not use jb weld because gas will deteriorate it over time. Jb weld is only epoxy.
    I would use silver solder with acid flux, much like how you would sweat copper plumbing in a house.
  13. lsoult

    lsoult Member

    Nice Elbow- I have the exact same frame from Wally. I made my own elbow out of copper pipe and JB welded it on. It looks like ****.

    Is you elbow a simple plumbers fitting?? I might change to that.

    Thanks for posting the pic :)
  14. oldguy387

    oldguy387 Member


    The elbow is from Home Depot plumbing dept. About $2.00. As for the fitting to the intake, as I said, I cut 4 slots in the intake so that it would crimp around the elbow. I will be fine tuning, but my problem with idlewas the choke (I think, as I am mechanically inclined). What was happening, was as I would ride with choke all the way ON, it was so loose it would open up by itself, causing the idle to go wild. I took off the air cleaner and tightened the choke down really tight. I can move it with one hand but now it stays where I put it. Idle improved 100%. Dale
  15. motorpsycho

    motorpsycho Active Member

    that's odd because by what you are describing, it couldn't be the choke.
    when you are riding with the engine warmed up you want the choke to be OPEN (or off). If the choke would close while riding, the engine would either quit running or run terrible.
    So if what you are saying is that you have to ride with the choke closed (or on), then you have a massive air leak (which i mentioned earlier).
    if the choke is open and your idle "goes crazy" this would also indicate an air leak.

    any time you have to have the choke closed other than on initial start up, indicates a bad air leak. by closing the choke you are cutting off the main air supply into the carb and the air leak is supplying enough air to make the engine run ok.
    remove the air filter assembly and start the engine like you always do. now, make sure that the choke s open (or off) now, put your hand over the carb throat. if the engine still runs, you have an air leak.
    when i say choke open (or off), i mean that the little disk on the end of the carb is not blocking the carb throat.
  16. oldguy387

    oldguy387 Member


    The book I got with the motor (from RAW) states that upon starting close the choke (lift the lever up - lowering the disc with a hole in it) and as you ride lower the lever as the engine warms up. My choke was so loose that I could not go 10 feet and the choke lever would work its way down so that the choke was fully open. ergo - high revs when clutch was disengaged. Now after running and the choke tightened, The idle is ok after engine warms and I have opened the choke. I still have to fine tune but things are looking up. I don't think I am getting an air leak at the intake, but I am going to take precautionary measures this weekend just to make sure. Dale
  17. motorpsycho

    motorpsycho Active Member

    yes, close the choke to start a cold engine. let it run for a few seconds and then open the choke (lever up is choke closed, lever down is choke open).
    really, when you choke the engine on start up you shouldn't need it to be closed for very long. you can close it all the way and start the engine, then quickly move it to about the middle position and work the throttle (don't ride off yet).
    don't take off riding until the engine is running and idling on it's own with the choke fully open.
    if you try to ride with the choke closed or 1/2 closed the engine will run terrible and have very low power.