Blew the Motah today o.O

Discussion in 'Motorized Bicycle General Discussion' started by Cylon, Apr 21, 2016.

  1. Cylon

    Cylon Member

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    Today my wife was riding her bike to work about 15 miles away and her engine seized up. Was a pain in the ass to pull the motor apart, the metal was all melted together.

    Swapping the motor out for a new one tonight when I get out of work at midnight.

    I estimate it ran for about 850 miles before the failure. Mixing at 32:1 and it was stock. I plan on adding a 6.0 cc head and a banana pipe for the next motor tonight. I hope that should keep it cooler.

    I have a spare reed somewhere too but last time I tried it I didn't like it on my bike.

    [​IMG]
     
  2. allen standley

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    So does it look like pin retainer clip failure or an exploding wrist pin bearing? I can't tell.
     
  3. Cylon

    Cylon Member

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    Wrist pin bearing was okay. The wrist pin itself had the bearing melted into it then looks like the piston dome smacked the transfer port.
     
  4. allen standley

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    OUCH! Da--it. Hey your bike good right?
     
  5. Cylon

    Cylon Member

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    Nope I'm building an exhaust for it tomorrow I get out of work at midnight so I'll probley spend my night listening to music having a few beers and replace that motor with a new one. I'm just bolting a whole new engine in there shouldn't take to long.
     
  6. allen standley

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    I just sent you a P.M.
     
  7. Nashville Kat

    Nashville Kat Active Member

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    Keeping things stock has some advantages I think- just bolt the stuff on a new motor and go. I always keep in my mind the Chinese Junk- the little boats that have been a way of life in the Oceanic Asian regions for centuries. It's not that the motors are "junk"- it's that we're really dealing with something conceived to have a great practical value first, for teaming millions we've been fond of dropping gasoline on.
     
  8. allen standley

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    Valuable perspective. Thanks Nash.
     
  9. Kioshk

    Kioshk Active Member

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    That wrist-pin is SUPER PITTED! How'd the motor sound before it detonated?
     
  10. maniac57

    maniac57 Old, Fat, and still faster than you

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    Are you SURE it had oil? Sure looks like a classic dry seize to me.....
     
  11. Cylon

    Cylon Member

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    Yep drained the gas and it was blue just mixed 2 gallons of 32:1 last weekend. All the other bikes have been fine on that gas.

    She said it slowly just died then locked up the rear wheel.
     
  12. maniac57

    maniac57 Old, Fat, and still faster than you

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    Sure sounds like one too. Most likely a cylinder plating failure then.
    I hear there have been a rash of jugs with bad spots lately, and I recently saw one myself with a dime sized defect, luckily BEFORE using it!
     
  13. Kletus

    Kletus Member

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    Could have been a bad crankshaft oil seal. This will cause a super lean mixture due to air being partially sucked in through the bad seal instead of the carburetor thus leaning out the mixture. I've repaired several 2 stroke motorcycles that befell this fate. The best thing to do if you have a means to do it is to have the bottom end pressure/vacuum tested. It also could have a splitline seal failure or a crack in the crankcase. A quick and dirty way to check for a bad oil seal is to spray starting fluid around the seal area, if your engine picks up a lot of RPM you probably have a bad oil seal.
     
    #13 Kletus, Apr 24, 2016
    Last edited: Apr 24, 2016
  14. Cylon

    Cylon Member

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    i just ordered a new motor for 130 bucks problem solved.
     
  15. Kioshk

    Kioshk Active Member

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    A standard engine for $130, or a kit?
     

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