Clutch clutch in = idle high? chinese 2 stroke

Discussion in 'Transmission / Drivetrain' started by solitus3989, Jul 26, 2008.

  1. solitus3989

    solitus3989 Member

    chinese 2 stroke engine from powerkingshop on ebay. installed 2 weeks ago.

    yesterday, i replaced the spark plug with an NGK-bh6s and a spark plug i found in my garage.

    when i hold the clutch in today, it idles very high. much higher than when im actually cruising. when i hold in clutch, it sounds like im WOT when im 0% throttle.

    also, if i leave clutch engaged, at 0% throttle, it cruises along at 10mph.


    problem with the clutch? does the clutch just need tightening?

    also noticed boot on top of spark plug got very hot. never touched the boot after riding. normal or bad?
    should i put my old boot/plug on?

  2. Skyliner70cc

    Skyliner70cc Active Member

    There is an idle adjustment screw on the left side of the carb. use it to slow your idle speed. An engine will always spin faster at the same throttle setting under no load then when under load.

    Its not unusual for engine idle speed to increase noticeabely as engine break ins. It is also not unusual for intake gasket to blow on a new build and cause an airleak which leans mixture and causes engine rpm to go high. I wouldn't be surprised if your intake gasket is shot. I never use stock ones and make my own on a new install. See my list of tips I posted for some things that can go wrong with these engines.

    The hot boot is normal. Its just dissipating engine heat that is conducted via the plug.
  3. Mountainman

    Mountainman Active Member

    Skyliner has you best interest covered above in regards to your rough idle. I was reminded yesterday when I went to buy (first time) new spark plug at a small engine repair shop. The gentleman said that he didn't show any numbers so as to cross reference and IT WOULD NOT BE A GOOD IDEA TO JUST PUT ANY PLUG IN MY ENGINE -- even though it may look the same -- some burn cooler and some burn hotter -- get a plug that burns to hot -- he said that it could even possibly -- burn a hole in the piston ?? I am not real sure about that -- but -- who would want to take it to test ?? Happy Riding from - Mountainman
  4. solitus3989

    solitus3989 Member

    the engine is breaking in, so i will need to gradual decrease the engine idle speed manually via the screw?

    also, why am i lulling forward at 10-15mph when the clutch is engaged but i am at 0% throttle? that never happened before. it should just slow down and die if i don't disengage the clutch...

    i also looked carefully on the forums, and the NGK-B6HS was recommended here.
    i also gapped it to .20
  5. Skyliner70cc

    Skyliner70cc Active Member

    If you idle is too high your speed will also be too high when you aren't rolling in any throttle.
    Where are you located? Perhaps there is someone in your neighborhood who could mentor you during your first install?
  6. solitus3989

    solitus3989 Member

    i am located in appleton, wisconsin.

    not too many users from WI, i don't think. most from down south.

    and i will try to adjust the idle screw now.
  7. stude13

    stude13 Active Member

    hi; i just went on first run with the same engine and had the same outcome. i thought of vac. leak right away. i used some flamable aerosol and located vac. leak at carb to manifold connection. will try fix soon. good luck. mitch
  8. plato

    plato New Member

    Idle adjustment help needed

    I just got my so-called 80cc mounted and took the bike for a quick ride up and down the street. I can see an addiction coming on.

    Quick question - I am trying to adjust my idle, but turning the idle screw in or out does not seem to affect the idle. Any suggestions would be greatly appreciated!

  9. Sianelle

    Sianelle Guest

    Have you got some slack in your throttle cable? If your throttle cable is too tight it can raise the idle speed and the idle adjustment screw won't make any difference.
  10. dldennis

    dldennis New Member

    Remove the throttle assembly cap and pull out the assembly

    Make sure the assembly is properly fitted with the cable in the notch on the bottom of the slide

    Important: slide the the throttle assembly back in the carb and place the split so it slides over the notch in the side wall of the carb. If the split is not over the notch the assembly is not properly seated and the engine will idle very fast!!!
  11. plato

    plato New Member

    Thanks guys - it seemed to be that the throttle cable was too tight. The angle tube/piece that comes out of the bottom of the throttle was not screwed in all the way. Once I screwed that in, the motor idled slower and I was able to use the adjustment screw to adjust it.