Compression after 9 Months

Discussion in 'Motorized Bicycle General Discussion' started by Wheel Rush, Mar 31, 2009.

  1. Wheel Rush

    Wheel Rush New Member

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    Howdy Mates, Its been awhile.

    I have had this 80cc running now for about 9 Months, and put a few miles on it a week,

    to give you an idea, I doubt that I have used more than 7 gallons of gas, but recently

    noticed, it runs OK, but it seems a little harder to kick off, meaning, . . It used to pop off easily

    and start right up, however now it doesn't fire on the the first try, after a hardy pedaling,

    it fires and starts up. Has the compression changed that much or should I start checking

    further?
     
  2. azbill

    azbill Active Member

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    is the gas mix old ?
    2stroke mix gets stale pretty quickly (within 2 weeks, I think)
    check you plug as well ...might be fouled
    mine has a little under 4k on it and takes forever to start now
    (I should shoot it and put it out of it's misery, but I need it till my new drivetrain comes in)
     
    #2 azbill, Mar 31, 2009
    Last edited: Mar 31, 2009
  3. Wheel Rush

    Wheel Rush New Member

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    I guess it could be as much as two weeks, but that would be about it.

    I'll try to spray some start up fluid into it next time to see if it will kick

    faster and easier.
     
  4. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    Sounds like a tired plug? What plug? How old?
     
  5. Wheel Rush

    Wheel Rush New Member

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    Hi Pablo,
    It's an AGK B6HS, its been in for 7 Months, and is pretty well carbon coated, but not really caked. Whatya think ?
     
  6. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    NGK right? I would change plugs. Low cost, simple things first.
     
  7. Sydneysider

    Sydneysider New Member

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    I had some similar probs, and found the muffler was chocker blocked with carbon.. cleaned it right up and it fired up right away and the power was back up again. Hope this helps.
     
  8. Wheel Rush

    Wheel Rush New Member

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    OK, Thanks I'll get on it, . .

    It more than likely is one of the two of those, The things is with most start up even if it needs another try, you can here the compression stroke exhausting, But on the occasion I am getting nothing but a slow gruel to a hard pedal stop, I do not hear the compression escaping.

    I'm not sure exactly what to think about that, . .?

    Is that do to the fact that a burn combustion is pushing out the exhaust valve with enough pressure that it is causing the sound of exhaust escape?

    If so, I guess then a clogged muffler would have similar results,

    I think you guys know your 2 strokes.

    I'll let you know.
     
  9. Goat Herder

    Goat Herder Gutter Rider

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    Does it have power after warming it up? Mine was pretty wore out for compression at 5000 miles when It finally just didn't have power but it would start right up! Maybe spark dunno. I saw old gas give these CH a bad attitude.
     
  10. Sydneysider

    Sydneysider New Member

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    Most likely. I found with mine when I opened full throttle at idle, it would rev extremely slowly at first but once it hit that higher rev, it would shoot right up meaning that there was enough pressure to escape out of the engine.
     
  11. Wheel Rush

    Wheel Rush New Member

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    I'm not sure I understand that because, . . once the spark ignites the fuel,
    that very first sparked ignition is going to bring back an exhaust pressurized emission, that in my line of thinking can not be missed.

    Having said that, the thing is when the engine has run for awhile, a mile,
    then shut down, and has been off maybe 15 mins. no Problem, starts right up, so if it is the plug, . . then it must pop off better in a slightly warm engine, !
    However if it has been running only a few mins, than restarting seems to lag behing resulting in a hard slow start.

    I took out the muffler guts, notta!
    I'm on my way to pick up another plug, . . let you know.
     
  12. Norman

    Norman LORD VADER Moderator
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    sounds like a almost dead spark plug. One easy to fix with a fresh plug.
    Normandnut
     
  13. Wheel Rush

    Wheel Rush New Member

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    Not a Plug, When I removed the baffle in muffler still no results,
    It starts and runs as usual, but it doesn't start as usual, it really hard pedals and still wont budge, I'll loosen the manifold connection tomorrow and try it.
     
  14. Sydneysider

    Sydneysider New Member

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    You know.. I did the same thing I took the baffle out, it seemed to be ok but guess where it was all bogged up.. right at the bend where you cant see it. I checked by blowing through the muffler and end it up with a red face!

    Thats where it may be clogged in yours..
     
    #14 Sydneysider, Apr 3, 2009
    Last edited: Apr 3, 2009
  15. Wheel Rush

    Wheel Rush New Member

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    I'll double check that, but I did loosen the muffler pipe from the manifold, . .

    I am believing this is a clutch related situation, just a guess.
     
  16. Sydneysider

    Sydneysider New Member

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    should be really easy to blow through.. Good luck
     
  17. Cabinfever1977

    Cabinfever1977 New Member

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    lucky i have a pull start,starts up first time everytime.if that breaks i can peddal start it.
    and in 9 months i'll probally buy another engine kit and bike.
    to change my plug i would have to take the motor off(tight fit),so im not as long as it still works.
     
  18. Wheel Rush

    Wheel Rush New Member

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    Yeah, . . but there is something going on here and I can't figure it!

    I checked the exhaust There isn't any obstructions and I blew through the muffler it wasn't like a clear pipe , but I did blow through it, your not saying it should be really easy to blow through a muffler are you. This is not the stock muffler its a TOMOS, but I don't think any of them are really easy to blow through, there IS a Baffle in there.
     
  19. Sydneysider

    Sydneysider New Member

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    It is possible that it may have developed an air leak somewhere and a lean mixture is causing a delayed start due to more air.

    When the engine is hot, it starts up right away?
     
    #19 Sydneysider, Apr 9, 2009
    Last edited: Apr 9, 2009
  20. Wheel Rush

    Wheel Rush New Member

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    It starts up every time but it passes the point where it started up with a fairly fast pedal and I could practically coast while engaging the clutch, and it started, . . now I have to pedal at that point and after the clutch is engaged I still have to pedal against the compression, and after a few revolutions of the pedal it starts kicking slowly and starts.

    I am thinking you might have something there with the lean mixture, not sure about air leaks.

    Whats the story there ? If I recall spraying around sealed joints with carb cleaner or what?

    Would you change the mixture to something a little richer ?
     

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