Engine Trouble Idle Help Wanted

Discussion in '2-Stroke Engines' started by openscreen, Aug 10, 2011.

  1. openscreen

    openscreen Member

    Thanks to this forum's members for helping me get my bike running. Much appreciated. The engine moves the bike along at a great clip, the only problem being that it will not idle. I checked a ton of threads related to idling and none of the proposed solutions worked. The things I tried so far are: installed a new spark plug with the proper gap, made sure the carb slide was installed properly, made sure the C washer was on top of the needle C clip and tightened carb and exhaust connections to eliminate air leakage. The only modification I made when putting the bike together was to install an extra heavy slide spring. Because of resistance caused by the way my throttle cable was routed, the stock spring was not strong enough to sap back the throttle. When i first ran the engine the idle was fine. Then the bike went into storage for a while. And now I can't get it to idle. Any help you can offer would be great.
     

  2. motorpsycho

    motorpsycho Active Member

    have you tried turning in the idle adjustment screw?
    did you remove the idle screw to make sure that it has a tapered and on it like it's supposed to?
    is the idle screw even there? (sometimes they can vibrate loose and fall out).
     
  3. openscreen

    openscreen Member

    hey,motorpsycho, thanks for the reply. It has an extreemly small taper starting about 1mm from the end and at about 45 degrees.
     
  4. motorpsycho

    motorpsycho Active Member

    another thing to check is the main jet. they have been known to back out and fall into the float bowl on some carbs.
     
  5. openscreen

    openscreen Member

    Thanks again, motorpsycho. The main jet seems to be fine, definetly not sitting on the bottom of the bowl. I know very little about engines so this has really got me stumped. You have any other ideas?
     
  6. cloud_2901

    cloud_2901 Member

    Clean the air filter?
     
  7. HeadSmess

    HeadSmess Well-Known Member

    lower needle by a notch or two(raise c-clip). lean it out a bit at idle.

    take the spring off the idle screw and screw it in further...
     
  8. ken murphy

    ken murphy Member

    These lil engines don't idle well you can get em to by change'n the carb,or you might try opening up the pipe,and putting a bigger end on it(stinger)These lil china girls run rich for the most part,they are also detuned from the factory,take the carb off and look at the gaskett its reduced on most of em.
    The end of the pipe should be just under 5/8 dia O.D.But for stock motors 1/2 copper is fine,you will notice a good change just by doin that,egor has a slide modifacation that I've done successfuly.
    The simplest way for you increase the Idol would be with the adjustment that is on top of the carb where the cable comes in.
     

    Attached Files:

  9. Al.Fisherman

    Al.Fisherman Active Member

    Solution........ [​IMG]
     
  10. openscreen

    openscreen Member

    Thanks, cloud_2901. yup, the filter i clean.
     
  11. openscreen

    openscreen Member

    HeadSmess, I'll give it a try and let yoknow how it works. Thanks
     
  12. openscreen

    openscreen Member

    Hi, Ken MUrphy. Great looking bike.

    What exactly should I do with the 1/2 inch copper tube? Which way, higher or lower, do i move the carb-top adjustment to increase idle? I have not been able to find the post by igor. can you tell me where it is? Thanks.
     
  13. openscreen

    openscreen Member

    Hi again, Al.Fisherman. I much prefer pictures to words, and still I am not quite sure what you have done to the carb. I assume it is the tube attaced to the intake manifold. What is the other end attached to?
     
  14. Al.Fisherman

    Al.Fisherman Active Member

    The thread I quoted was to do with the idle screw falling out. I stated a solution, followed by a solution... I posted a picture of the carburetor, the idle screw is as plain to see as these letters I'm typing.

    As far as the tube.. it is the tube to the boost bottle.
     
    Last edited: Aug 11, 2011
  15. motorpsycho

    motorpsycho Active Member

    I disagree 100%.
    first of all, if you have a properly tuned carb these engines will sit and idle all day long (my 2 will anyway).
    adjusting the idle by lowering/raising the throttle cable at the top of the carb is a bad idea. this can make the cable pull too much when you turn left or right, making the engine accelerate as you turn.
    The best way to adjust the idle is by the idle adjustment screw.
    the stock exhaust just sucks anyway and the best thing to do is replace it with an expansion chamber, or to modify the stock baffle so the engine can actually breathe. The only way the stock exhaust would hinder the idle is if it's clogged up with unburned oil.
     
  16. motorpsycho

    motorpsycho Active Member

    one other thing to check...
    Have you looked at the choke plate to make sure that it's 100% open?
    sometimes the screw will work it's way loose and allow the choke plate to be partially closed even tho the lever is all the way in the open position.
     
  17. ken murphy

    ken murphy Member

    uneducated

    any adjustment can be used. how do you tune a carb w/no adjustment? pull what?100%? first grasshopper u must learn machinery and then ur opinion will be edgeamacated.
     
    Last edited: Aug 12, 2011
  18. motorpsycho

    motorpsycho Active Member

    how do you tune a carb with no adjustment?
    simple....
    you adjust the throttle cable up at the throttle on the handlebars.
    by raising the cable at the top of the carb, you are moving the slide up (or down) making the idle adjustment screw virtually useless. the only adjustment that you need to make to the throttle cable is to make sure there not too much(or too little) slack in the cable. You shouldn't adjust the idle with the cable.
    you also tune a carb by re-jetting it so it actually runs right.
    adjusting the float is also another good idea to get the engine to run right.
    No need to edgeamacate me on this stuff, i've been doing it for years.
     
  19. openscreen

    openscreen Member

    hey, Al.Fisherman, still at it i see. If you had read my earlier response to Motorpsycho, you would have known I knew exactly were the idle screw was. Instead you chose to write what feels to me like a snarky response to my perfectly honest question. It turns out the idle screw has nothing to do with my problem. Neither your "solution" nor your "solution" turned out to be a soultion. Everyone else on this site has been helpful and polite to me. I have found this, and your previous responses, hurtful and unhelpful.
     
  20. openscreen

    openscreen Member

    Thanks to all for your help. Unfortunstrly, while trying to fix the idle problem, I had to deal with the stretch in the throttle cable. It had gotten so long that the throttle no longer had much affect on the engine speed. Once I get the cable fixed, I'll get back to dealing with the idle issue.
     
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