Have I blown up my motor?

Discussion in 'Motorized Bicycle General Discussion' started by cyclepro101, Jul 1, 2009.

  1. cyclepro101

    cyclepro101 New Member

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    Well I finally had it going great. I got the SBP Tuned pipe and it was screaming. But I went out to start it and noticed it was hard to start and would not idle. Also there is no or very little compression. With the cluch out I can push the bike around the garage. Also when I get it going its very clunky, it will go ok for a while then just go CLUNK and stop. The fuel is 30:1 and fine. The plug is fine, very light charcol. The carb is perfect. I thought it was electrical as is goes ok but then going down a hill off the gas it just dies intermitenly. I started it up this morning for my son to have a listen and once I got it going all he said was "that sounds bad". Then CLUNK, it stopped. Still no compression.
    So what should I do. I have been ringing its neck flat out a bit lately should I just replace the ring? What else should I look for when I have the head and barrel off? I was told to check under the clutch cover as I may have blown and oil seal? Are these hard to change?


    Steve
     
    #1 cyclepro101, Jul 1, 2009
    Last edited: Jul 1, 2009
  2. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Sounds like you may have smoked it...look for scratches on the cylinder wall. You may get by with a new set of rings.
     
  3. cyclepro101

    cyclepro101 New Member

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    There is just no compression. Its hard to tell if an oil seal is gone. How much should or would be leaking out behind the clutch if it was gone?
     
  4. xlite

    xlite New Member

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    The seals, although important for operation, have little to do with compression. I would look at the piston, rings, and cylinder walls. Only takes a few minutes and tells a lot. Might be bearing gone and took the top end with it. Not costly to repair but sometimes better to just pick up a whole new engine for $75 and use old for parts.
     
  5. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    Quickly pop the head off. Too easy.
     
  6. freewheeling frank

    freewheeling frank New Member

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    sounds like broken rings or bad wrist pin bearings gotta pullthe head and jug
     
  7. cyclepro101

    cyclepro101 New Member

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    OK But what am I looking for when I get the head and jug off?
     
  8. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    Suspicious holes in the piston, alleged gouges in the bore, loose parts laying about....the usual suspects.
     
  9. fm2200

    fm2200 New Member

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    These engines are not good at screaming
     
  10. cyclepro101

    cyclepro101 New Member

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    OK, Thanks team. Check this out. I also e-mailed back to my Aussie supplier and he said he will E-mail the photos to China and he will send me a new motor.
    It looks like all the chrome came off the inside of the jug? Also there is bits of this metal? stuff in the bottom end too.

    Steve
     

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  11. Dave31

    Dave31 Moderator
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    Oochhhh... thats ugly :-||
     
  12. cyclepro101

    cyclepro101 New Member

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    Maybe 1:30 was too lean. Might pull back to 1:25. Or it could of just been a bad jug?
     
  13. Hawaii_Ed

    Hawaii_Ed New Member

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    I am thinking too lean for sure. At least the engines are cheap!
     
  14. city of angels

    city of angels New Member

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    sorry to hear about your motor at least they are going to fix it where did you get this motor from
     
  15. cyclepro101

    cyclepro101 New Member

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  16. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    They are pretty much all the same with slight variations. They come from a few different factories around China.
     
  17. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    30:1 was not likely too lean, however, you could have had the fuel to air mixture too lean. Tuned pipes usually require a bigger jet/more fuel.
     
  18. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    YES. Fail.


    Bad plating.

    NO STINKING WAY 30:1 is "too lean". Sorry but that's not an oil related FAILURE.

    So you told the dealer you rev'ed the **** out of thing and rode it like a raped ape and he gave you a new engine, no charge? Not bad!!
     
  19. Cabinfever1977

    Cabinfever1977 New Member

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    wow i cant believe those pics,now thats what i call engine damage
     
  20. 2door

    2door Moderator
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    Reminds me of my old fuel dragster days. I've seen the innards look like that after one run.
    Keep us posted on how your dealer is taking care of you. You might want to consider taking it a bit easier on your new engine. These are after all cheap, simple little motors that were never designed to take a lot of abuse. "Screaming" implies that you might have pushed the envelope a little. Good luck and keep us informed.
    Tom
     

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