Exaust smoke coming out sprocket cover!!

Discussion in 'Motorized Bicycle General Discussion' started by fall_down_stand_up, Aug 29, 2009.

  1. fall_down_stand_up

    fall_down_stand_up New Member

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    When im at a stand still with my clutch lever pulled in and I rev the motor exaust comes out of the cover by the clutch lever were the sprocket is....What is going on?bad seal?The engine boggs when I rev it up even at a stand still with the clutch pulled in....It takes it awile to rev up....Could this have to do with the exaust smoke coming out of the sprocket cover????Driving down the road my top speed is mabe 15mph and If I pedel with it,it will eventually hit the power band and go up to 25mph sometimes....Exaust is coming out of the muffler like it should....
    Thanks for any help
    John-John
     
  2. Dave31

    Dave31 Moderator
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    Sounds like a bad seal to me.............
     
  3. fall_down_stand_up

    fall_down_stand_up New Member

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    Would that cause the engine to rev up slowly and bogg?
     
  4. 2door

    2door Moderator
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    This is a strange one. If either side crankshaft seal was bad you wouldn't get exhaust from the clutch actuator cover. Are you certain that is what you're seeing? But to answer your question; a bad crank seal, or any air leak will cause a lean condition and poor performance. You can try the old carburetor cleaner method of looking for air leaks. Spray it around places on your engine while it is running and listen for distinct changes in rpm. The intake manifold gasket and where the carb slides onto it are the most common places to have an air leak. As for exhaust coming from the clutch actuator cover...you've stumped me there. Maybe someone else has seen this, I have not.
    Tom
     
  5. fall_down_stand_up

    fall_down_stand_up New Member

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    I am stumped as well,There is no air leaks from the cylinder to the intake or carb to intake....The engine idle's smooth,but I will spray some more carb cleaner on it and will fire it up tomorrow again and check it out and get back with you....
     
  6. GearNut

    GearNut Active Member

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    Spray the crankshaft seals as well. If you are concerned about the carb cleaner damaging the coating on the magneto, or washing the grease off of the gears, you can also use a propane torch. Do NOT light the torch, just turn on the gas and hold the tip as close to the seal as you can. if there is a leak, the gas will be sucked in and alter the idling as well.
    It also is way less messy.
    EDIT: Have a CO2 fire extinguisher handy as well. Do not let Murphy get his chance to play his folly.
    I personally hate Murphy's law..... :mad:
     
    #6 GearNut, Aug 29, 2009
    Last edited: Aug 29, 2009
  7. fall_down_stand_up

    fall_down_stand_up New Member

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    thats a great idea....I never stop learning new things on this website.....shft.
     
  8. Sydneysider

    Sydneysider New Member

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    my engine had the same problem like that 2 years ago, found out due to the displaced crankshaft seal the fumes were actually travelling thru the gear assembly and out the sprocket cover, believe or not! I just pushed the seal back in with a screwdriver and it worked :)
     
  9. fall_down_stand_up

    fall_down_stand_up New Member

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    Did you have to take the sprocket off to do this?Did the leak make your engine bogg?
    Thanks for the help
    John-John
     
  10. Sydneysider

    Sydneysider New Member

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    nah not really, all I had to do was push the seal back in evenly with a screwdriver thru the teeth of the crankshaft gear.. but do it carefully so as not to damage the small gear.. i dont think i can recall any bogging but there was a considerable amount of smoke coming from the sprocket cover especially when I gave it some gas. Hope this helps..
     
    #10 Sydneysider, Aug 30, 2009
    Last edited: Aug 30, 2009
  11. wog383

    wog383 New Member

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    I had same thing, smoke coming out on the clutch actuator side..I pulled clutch cover off and noticed oily buiild like on the spark plug...Seal under the main drive cog gone..It looked like it twisted off...Ordered a new one and engine had way more balls....Before it was pretty gutless, couldn't idle as well...
     
  12. Humsuckler

    Humsuckler New Member

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    my engine is loosing its balls :(

    naturally, as an educated, diplomized small engine mecahnic you would think id be ecstatic and eager to fix it back to top notch with the snap of my greasy fingers, WRONG. if its mine, i would rather run the piss out of it and get rid of it when its done.... i think ill keep ths one and do some performance rebuiling tho..... lol
     
  13. wog383

    wog383 New Member

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    can do that as well...My engine is only 5 months old...I got the new type high tempt seal from rock solid engines where i got my HP motor done..2 strokes are easy to fault find..Its spark, fuel or compression...
     
    #13 wog383, Nov 23, 2009
    Last edited: Nov 23, 2009
  14. Sydneysider

    Sydneysider New Member

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    I know this dude who had a 30 something cc motor and he replaced the pistons, crank and shaft and most components with high strength, light weight alloy steel.. power output boosted to 6kw or 8 hp on the dyno believe it or not.. and this was from a 2 stroke engine that was under 40cc!
     
  15. wog383

    wog383 New Member

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    Where did he get the parts from?
     
  16. fall_down_stand_up

    fall_down_stand_up New Member

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    Wow this is an old thread....My engine gave up on me and I bought a new one....It kept bogging and had little power,thought it seamed to have good compression....Oh well now im using another engine....
    John-John.shft.
     

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