speed carb problem please help

Discussion in '2-Stroke Engines' started by wackey101, Jan 28, 2011.

  1. wackey101

    wackey101 Member

    carb will only start and run on choke as soon as i put it back to normal it dies i have needle on the middle one
    thnx
     

  2. jhendrix

    jhendrix New Member

    Check your spark plug to see if your mixture is too lean or too rich and then try moving the c clip to adjust it and see if that helps
     
  3. motorpsycho

    motorpsycho Active Member

    if you have to leave the choke on, the mixture it may be too lean. (it's getting too much air and by choking it, you are reducing the amount of air that it's taking in).
    you may have to play with the air-fuel mixture screw (if it has one), or you have an air leak somewhere (check the carb to intake seal and make sure there is no extra air being sucked in around it.)
    moving the e-clip may help but you would probably want to lower the clip which will rasie the needle richening the mixture.
    my guess is an air leak tho because the engine shoudl still run without the choke on , even if the needle is set as lean as it can be. moving the needle will not lean it out enough to cause the problem you are describing.
     
    Last edited: Jan 28, 2011
  4. wackey101

    wackey101 Member

    thnx

    i will double check for air leaks today and richin th mix up today t do that i will have to change the e clip i will get back once i do it but if any one wants to help or give more ideas more please feel free to do so
    thnx
     
  5. motorpsycho

    motorpsycho Active Member

    the most effective way to richen the mixture (if you really have to) is to re-jet the carb.
    changing the e-clip will only help from idle to about 1/2 throttle because after 1/2 throttle the needle is totally away from the jet and hos no effect on the air-fuel ratio.
     
  6. wackey101

    wackey101 Member

    hey

    well i richen the mixutre as much as i could cover the air leakes it was were the intake was but still was bogging but at least it worked then i richen the mixure as much as i could works beautifully but still bogs but not as much and only if i go full throttle all of a sudden if i want to re jett it what size should i get to fit it cause i mine is the standerd
    thnx
     
  7. motorpsycho

    motorpsycho Active Member

    yes, as i mentioned, moving the e-clip on the needle will only help from idle to about 1/2 throttle. If it's still bogging, chances are that it's still too lean.
    USUALLY a bog at wide open throttle is caused by the fuel-air ratio being too lean.
    you will have to take your float bowl off and figure out what size jet is in it, and then go from there.
    I'm not sure what jets will fit this carb tho. sick bike parts sells many sizes of delorto jets, but I have no idea if the threads on those jets are the same as the threads on the jet that's in the speed carb.
    lets say that your carb has a .70 jet in it, you would want to richen it up to like a .72 or .74.
    always make jet changes in small increments (as far as the jet sizes go). you never want to make a big jump in size, like from a .70 to a .66.
    it takes time going in small increments, but this helps you fine tune it.
    lets say that you go from a .70 to a .72 and it runs better. now go from a .72 to a .74 and see how it runs. it it runs even better, then go frm a ,74 to a .76. if this change makes it start running worse, drop back to the .74 jet.
    there is a lot of messing around in tuning a carb by changing the jet. it's not like you can just guess and start throwing random jets in it to see how each one affects how the engine runs.
     
    Last edited: Jan 29, 2011
  8. wackey101

    wackey101 Member

    thnx

    thnx for the reply i will try what i can with the jet
     
  9. wackey101

    wackey101 Member

    speed carby smaller jets than nt carb???

    hi
    i have a speed carby and was bogging alot because was too lean i had the pin on the richest setting and still slightly boged so i had a look at my jet than had a look at my old jet turns out the stock nt carb has a bigger jet for some reason wich the speed carby is ment to be bigger as soon as i swapped the old one into the speed carby the bogging stoped but now my throttle is less responsive
    wich is really bigger please help
     
  10. Skyliner70cc

    Skyliner70cc Active Member

    Moast caurb jetz hav eh numbar onn them dat realats two da sise uv da jett. Cinse our caurbs donte hav a lo speid neadel valv, da mane jett iz a compramize att da eckspense uv tooning threwout da rpm rainge. Yoo hav two deside wat it iz u want hi spead powar than lo speid powar wil sufer an vice verse. Ef a fine tooned injun iz ur gole, than konsidar a CNS karb.
     
  11. english, please!
     
  12. wackey101

    wackey101 Member

  13. Dave C

    Dave C Member

    3rd possibility is the spark plug wire. Do you have access to a multi meter? I'm sure someone here can point you in the right direction. It's very difficult to diagnose an electrical problem without a meter. You can get them real cheap at Harbor Freight. I got a PDF fron BGF with the ohmages for the different connections. I think the ohmages are also located in a stickey on electrics.
     
  14. toojung2die

    toojung2die Member

    It doesn't look like you're grounding the spark plug to the head when you're testing it. My engine kit came with a defective CDI module right out of the box. The spark was weak and intermittent. I got a new CDI and it's been running great. I bought a spare magneto coil and CDI in case one fails in the future.

    I tested the defective CDI and working CDI with an analog Triplett meter and a digital Fluke. The results varied depending on the meter type used to test. Neither meter gave me the values I found others had posted for working CDI modules. The magneto coil values were comparable. The low quality of the components used to make the CDI's probably have wide tolerances giving wide variances in the resulting ohm values.
     
  15. motorpsycho

    motorpsycho Active Member

    Junk plug wire and boot, junk connectors on your wiring.
    Those connectors give a lot of resistance. Get rid of them and solder all of your wire connections together and heat shrink them. Those connectors can break internally from vibration and they can become loose over time. They are actually made for speaker wire which is very low voltage.

    Get rid of the stock spark plug wire and boot, and get an automotive wire with a rubber boot.

    These 2 things may not be 100% of your problem, but they are things that I would consider changing if i were you.
     
  16. Stan4d

    Stan4d Banned

    Before I did anything else, I would listen to this piece of advice.
    That would help narrow it. You said it would back fire.....it that current, or does it not even try to start. If you find a good strong spark and backfiring but will not start let us know.

    If that is the case I can solve it in 2 words. Woodruff key.
     
  17. wackey101

    wackey101 Member

    d

    first of all thnx for all the messages but motor shyco the plug is not stock neither the spark plug boot its upgradded and i am goning to solder my connections but not now when i get a new cdi i probly will but is it the cdi or magneto
    thnx
     
  18. wackey101

    wackey101 Member

    no i dont have a multi meter unfortunately
    thnx how do i take the spark plug wire off because when i try turning it clock wise it wouldent come off
     
  19. toojung2die

    toojung2die Member

    Lefty-Loosey, Righty-Tighty. Turn the wire counter-clockwise to remove it from the CDI module. Get a multi-meter for ten bucks or less and learn how to use it. It'll come in handy for the rest of your life.
     
  20. wackey101

    wackey101 Member

    g

    it wont come off even to the left
     
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