seized up

Discussion in 'Motorized Bicycle General Discussion' started by Evan, Jan 23, 2010.

  1. Evan

    Evan New Member

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    My motor seized up this afternoon and when i took it apart there is a pin sticking out of the top of the piston. at first i thought it was part of a needle bearing but it looks to be one of the pins that is in the gap of the rings. any thoughts as to what would have caused this? It was running beautiful right upto the point that it quit. Hey GhostO, You available for parts on a sunday if I can get north?
    Any input is appreciated, Evan :-||
     

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  2. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    I'm not sure Jim has an engine laying about.

    You are best just buying a new engine. Cheap Chinese engine lottery.
     
  3. stv1jzgte

    stv1jzgte New Member

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    Ow bugga that sucks big time, i once had the wrist pin bush do similar things to the top end of a motor.
    Give the botton end a good cleaning just to make sure there no more bad stuff in there.
     
  4. wjliebhauser

    wjliebhauser New Member

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    Bummer. That gouge in the cylinder wall will be hard to hone out. I think I'd be inclined to go for a new engine. Looks like all you really need are the cylinder and piston, if you can find 'em cheap enough. Sorry for the bad luck.

    I'm new to Chinese bike engines, so I just bought one and bolted it up. So far, so good. After reading all the good info here, if I build another, I'll tear it down and inspect/check, install 'real' headbolts and such. Right out of the box. Good news? It's not like popping a rod in the in your fresh 383 overhaul. $$$$$$$$$$$! Nowadays, I like and can afford Chinese bikes much better!

    Good luck Evan!
     
  5. GearNut

    GearNut Active Member

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    Ugh! The dreaded "howtheheckdidthathappen?" failure. Those are the worst!
     
  6. Sydneysider

    Sydneysider New Member

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    I found quite a few people including myself having that same problem in the past, apparently its the cheap wobbly bearing that was used in the crankshaft I am told. Since I switched over to the precise Japanese made needle bearing, I have never seen that happen again. I would throw that one away and get an engine with higher quality needle bearings.
     
    #6 Sydneysider, Jan 24, 2010
    Last edited: Jan 24, 2010
  7. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    That's the ring aligment pin (anti-rotation pin). Yes, they fall out. Yes your engine is toast. You could clean it all out and try a new top end, but that's a crapshoot if you leave even one flake of metal in there.
     
  8. Evan

    Evan New Member

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    well i guess the next question is what kind of 'motor only' to buy? I could just get another china kit but would rather find a motor that will last. what do you guys think is the motor to go with or all they all china made and some just with better bearings?
     
  9. Sydneysider

    Sydneysider New Member

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    I got a Skyhawk 48cc on mine, 3000 miles on it and going strong.. still has plenty of compression
     
    #9 Sydneysider, Jan 25, 2010
    Last edited: Jan 25, 2010

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