Engine Trouble Skyhawk GT5A 66cc extreme bogging

Discussion in '2-Stroke Engines' started by P3_Takuto, Sep 15, 2016.

  1. P3_Takuto

    P3_Takuto New Member

    Very recently my Skyhawk 66cc started wanting to bog with any throttle applied other than idle, even at idle (which sounds terrible) any throttle application bogs and will cut the engine , it has an NT Speed Gen 1 carb which has been great up till now, and a 40mm boost bottle. I've tried all sorts of methods to fix this myself, removing the boost bottle, tuning the air/fuel screw along with adjusting slide needle clip and readjusting the float bowl, I've got no where and anything I try shows no signs of improvement I've sometimes been able to get a high rev out of it but there is absolutely no power to it and bogs right back down, I've done a plug chop and it comes out wet and sometimes dry but too light at some points. I'm not sure weather to think it's too rich or too lean now, haven't been able to get out of idle much and when I do it is awful. If anyone has any suggestions please help, I've been at this for days!
     

  2. KCvale

    KCvale Motorized Bicycle Vendor

    It's a good engine so I suspect either an air leak between the carb and engine, or you have a pool of gas in the crankcase.
    Just pull your plug out, turn the gas off, then pedal it up the street and back with the clutch engaged to blow it all out.
    Thats one of the first things we check for repairs.
     
  3. crassius

    crassius Well-Known Member

    if it smokes way too much, then fuel in motor is the problem - keep it running till it clears itself out, and remember next time to turn off petcock when motor isn't running
     
  4. P3_Takuto

    P3_Takuto New Member

    Just finished and no changes after trying it, w.o.t kicks a little but quits just as quickly.
     
  5. P3_Takuto

    P3_Takuto New Member

    No visible smoking but I'll keep trying to run it.
     
  6. Nate888

    Nate888 Member

    check your choke first of all to eliminate the easiest problem it could be

    also see if air filter is restricting air flow. disassemble & clean your carb. I use clean gas in a spray bottle, but carb cleaner is better

    make sure the path from the carb to the combustion chamber has no air leaks

    electrical problems could maybe cause something like this if there's a connection that partially disconnects under greater wind & vibration, or a loose piece of something grounds out your CDI intermittently when you try to rev the motor
     
  7. Nate888

    Nate888 Member

    another thing to remind yourself to check even though it's obvious: make sure fuel is present, mixed right & able to flow into the carb. running out of gas when you're convinced you shouldn't have run out yet, could temporarily cause this problem as well. it's happened to me lol
     
  8. skyash

    skyash Active Member

    Blocked jet?
     
  9. crassius

    crassius Well-Known Member

    did you check the vent in the gas cap? or check the flow by taking out bowl drain and turning gas on?
     
  10. Arty

    Arty Active Member

    Another thing you might check is the muffler. Depending upon how many miles are on it, some of these little two strokes tend to plug up the muffler after awhile. - It has happened to two of my friends. - Just remove the muffler and try blowing through it. If it's clogged - you'll know it. If it is - try burning it out with a propane torch.
    I think the problem occurs more often if you use synthetic oil- since it has a higher flash-point than non-synthetic, so tends to build up rather than coming out as smoke.
     
  11. crassius

    crassius Well-Known Member

    just recalled seeing this once when slide was in upside down in carb - surprised me it ran at all
     
  12. Nate888

    Nate888 Member


    oh yeah! that reminds me, it could also be caused by hooking your fuel line into the wrong hole (vent [or venturri?] holes, I think??) on the carb, or if you connect the one vent hole to the other w/ the spare fuel line often present in these kits. source: my own dumbassery
     
    Last edited: Sep 15, 2016
  13. P3_Takuto

    P3_Takuto New Member

    Oh boy lots of replies. Ok I've checked the 'choke' (fuel enrichment port) and from what I can see it's as much in the off position as I can put it, I've completely taken apart the carb and put it back together checking for anything that would yield leaks and nothing out of the ordinary, I've shrink wrapped my connections but the CDI Is aged being from 2013 but I know the spark is okay so far. Cap vent is okay because checking the flow through the fuel line including a good fuel filter it's quick and smooth. The exhaust pipe is clear as well with no restrictions in airflow. I may try out a different carburetor to see if I can narrow down where the problem lies weather with the engine, carburetor or fuel delivery.
     
  14. Nate888

    Nate888 Member

    check the spark gap while you're at it. it could be part of the problem. depending on your altitude, fuel, engine timing, spark plug, CDI voltage, etc., the best setting usually varies between 0.018" & 0.036" (about .5-.9mm). see where it is, then give it a few tests at different settings & see if it helps
     
  15. crassius

    crassius Well-Known Member

    good idea, the standard NT carb is cheap and easy (I really like the original clone that has chinese chars on it)
     
  16. KCvale

    KCvale Motorized Bicycle Vendor

    You can what the 'butterfly' for the choke is doing buy just taking the air cleaner off.
     
  17. P3_Takuto

    P3_Takuto New Member

    Okay after a couple days of riding and switching carbs and using an NT Speed Gen2 it has better results. it's acting better but it still has some issues, it will bog like it did before until it warms up, anywhere from 1/3-3/4 of throttle still bogs unless it's w.o.t. After getting up to speed at w.o.t I can feel it 'coughing' and bogging again, the idle also seems off as it seems to be unstable. Acting like it has too much air and then trying to gear in it has too little power to gear in and stalls.
     
    Last edited: Sep 20, 2016
  18. crassius

    crassius Well-Known Member

    not sure what "gear in" means, but these will not take off from a standing start - when motor is running, one must pedal up to speed a bit before the clutch can be eased out
     
  19. P3_Takuto

    P3_Takuto New Member

    I've never had any problem with taking off from a standing start before. Also I don't have working pedals on my build.
     
  20. jaguar

    jaguar Well-Known Member

    bad crank seals can cause those symptoms
     
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