Bogging at top end

Discussion in 'Introduce Yourself' started by Mouse, Jan 1, 2016.

  1. Mouse

    Mouse New Member

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    I've had this bike for a while and its run good but now when I ride it it will run well then bog run well then bog at top end of rpm range any thoughts on it
     
  2. Blakenstein

    Blakenstein New Member

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    My first thought on that is carburation. My second thought would be spark plug, and lead, . Anyway, HAPPY NEW YEAR.
     
  3. 2door

    2door Moderator
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    Welcome to the forum, Mouse.

    We ask that when you post a question that you tell us a few important things along with your question.

    What engine do you have.? Is it a 2 stroke or a 4 stroke? What carburetor? If a 2 stroke, what is your fuel to oil ratio? Any information you can provide will help us offer help and advice.

    Tom
     
  4. Mouse

    Mouse New Member

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    The bike is a 2 stroke 48 cc Skyhawk I opened up the carb and my float is not attached to anything could that be the problem?
     
  5. Mouse

    Mouse New Member

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    Fuel ratio is approx. 30:1 and it has a stock carb
     
  6. 2door

    2door Moderator
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    The float, white plastic donut, does not attach to anything. It is free floating but does push upward on a small brass horseshoe shaped part that in turn presses against a needle valve. As fuel level rises in the bowl the float lifts (floats) and closes off the fuel inlet to control bowl fuel level.

    Your fuel/oil ratio is good. Stick with it.

    Are you still having the 'bogging' issue? How many miles have you put on the engine? If less than about 200 miles don't worry too much about performance. I doubt that are running lean so your bogging might be the normal situation you'll see with a new engine.

    Tom
     
  7. Mouse

    Mouse New Member

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    I the motor is a few years old I started with looking in the carb for dirt then I emptied the gas tank and put new fuel in then I replaced the box with the spark plug wire coming out of it then I ran Lucas carb cleaner through it.
     
  8. 2door

    2door Moderator
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    The box with the spark plug wire is your CDI, or ignition module. The wire is okay to use but you should replace the part that connects to the spark plug. That is called a 'boot'. You can get a good automotive quality one at any auto parts store. Also replace the kit spark plug with a better plug. Many of us prefer the NGK B-6 plug.

    When you ran the carb cleaner through did you mix it with your fuel or just spray into the carb? I'd be careful running it in your fuel. Too much and you might dilute the oil enough to reduce its lubricating properties.

    You said the engine is "a few years old". Did you build or buy this bike from another person?

    Tom
     
  9. Mouse

    Mouse New Member

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    Cdi brand new spark plug connection good ran cleaner in fuel compensated with more oil
     
  10. sbest

    sbest Member

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    Then that is not 30:1 any more, unless it was 50:1 to start with.

    You cannot "compensate with more oil" for anything. It just messes everything up.

    So, symptom = wavering bog at WOT (wide open throttle).
    You need compression, fuel, spark and timing to run, so:

    Compression? Any good?

    Fuel? Got enough? Pull line off carb and check flow. Does it pour out or trickle?

    Mixture? Warm it up and put a new spark plug in.
    Run it WOT for a few minutes, shut it off, clutch and coast to a stop.
    Pull the plug and have a look at the base of the electrode insulator, way down deep inside the threaded shell. Is it black, brown, tan, light grey or white? If it is black you are too rich. If it is white or light grey you are too lean. Jetting issue.

    Spark? Put it on a center stand or upside down (good luck with the tank!). Pull the plug conneted alongside the motor. Crank the pedals in the lowest range and watch the spark (I didn't say it would be easy). Is it yellow and snaps or is it blue and quiet? If it is blue, replace the plug first, then go further.

    Timing? Timing lights don't work well on these motors so best to check the mechanical integrity of the magnet and coil and electrical connections.

    This should be a good start.

    Steve
     

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