Engine Trouble new two stroke problems help please!

Discussion in '2-Stroke Engines' started by willE, Jul 7, 2011.

  1. willE

    willE New Member

    I am new to dealing with two stroke engines and can use some advice. I just installed a new two stroke 80/66 cc engine on my bicycle. After the initial roadblocks getting her going she was running pretty well. I had run maybe a half a tank or so when i gave it almost WOT (too early i think). After that it has been having problems idling, the sound of the engine and smoothness have gotten worse, and it is dying a lot. Now i will give you the details about my set up. I have always started it with the choke usually all the way down or almost all the way down. Even before i had any problems I had never been able to start it with the choke up and if i put the choke up it will kill the engine. I have checked the gas line and i know that the engine is getting fuel. The bike will run but it is difficult to start and keep running. It sounds like it is uneven (not making a consistent sound) like some of the strokes are more powerful than others. Sometimes it will not idle, other times it will idle and sound much better, but when i release the clutch and load is put on the engine the off balance sound and feeling comes back. I have tried adjusting the idle screw on the carb but it does not improve the problem really. The spark plug, when pulled from the cold engine is black and dry. I have also noticed the spark plug coming loose but problems persist even when it is thoroughly tightened. I am also not really sure how much torque these engines normally have but it will die trying to start from a stop if i am idling or going up a hill at a slow speed. The problems started after i gave it more throttle than normal for break in so I am wondering if i may have permanently damaged it :/, but I am hoping for the best. Any help with this will be greatly appreciated.
    Thanks so much,
    Will E

  2. Lazieboy

    Lazieboy Member


    My new motor is kinda weak but after break in time they do get more power. WOT is not good for new motor (less than 2 tanks) or so. Plug sound good. maby cdi issue?. or Ele. connection. Your answers are soon to come.
  3. Al.Fisherman

    Al.Fisherman Active Member

    Replace the plug with a NGK and a new plug lead. Have you taken a compression check or even checked the head gasket ..it may be blown. The screw on the carburetor only adjusts the idle. Have you made any modifications to the engine, have you checked the head torque?
  4. HeadSmess

    HeadSmess Well-Known Member

    um, whats the problem? it really sounds like a normal ht to me...dies starting from standstill while idling, dies going uphill slow... idles inconsistently like any other twostroke.one stroke sounds more powerful than the others... dies if you so much as wink at it...


    check the carb. always pays to give em a clean and a tweak before running. they have a total of...counts quickly... 10 or 11 parts. dont worry. watch how you pull it apart and reverse the process when the time comes. :)

    ignore all the hype about break in. theres no such thing. just over active imaginations kidding themselves.
  5. q999

    q999 Member

    the simple checks no special tools.

    simple things most often stop us cold.
    my advice check compression by removing plug and put thumb over hole while turning over engine by pushing bike or remove chain and use spark plug tool. should almost push thumb away with force. while the plug is out.. you can ground it (plug) out by holding against head turn over engine and look for spark, no spark ...new or clean plug and check wires ,, ground short on wire or too much load for a light could be an issue.
    carb should run wide open without too much problem ...the trick is a good idle and theres a hole section on that.
    good luck
    Last edited: Jul 13, 2011