My Girl packed it in

Discussion in 'Motorized Bicycle General Discussion' started by Dasmailca, Aug 29, 2013.

  1. Dasmailca

    Dasmailca New Member

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    :-||My first china girl finally worked excellent after much advice from the forum, and lots of tinkering, although it did vibrate a lot. After 600 miles though it seized up solid at about 20mph bringing me to an abrupt stop. I blamed this on an incorrect break in, in which I had made a mistake with fuel mixtures.
    I had bought 2 more motors however, planning on 2 more builds, so I just swapped out for one of the new ones. I followed proper break in procedures.
    The new motor worked excellent from the get go. I rode to work daily about 20 miles each way almost nonstop on a rural road at aprox. 20-25 mph.
    After about 4& 1/2 weeks , over aprox. 2 days I noticed a significant loss of power to the point where it would not climb a small hill. I suspected a loss of compression. When I removed the head I discovered a not so small groove scored in the cylinder wall as well as small pits in the head. Even a small piece of metal embedded there. It seems that something in the bottom end has disintegrated. Is there any thing I can do ? Are there better quality parts to rebuild with ? Is there a better quality engine to start with ? Maybe 4 stroke would be a better choice ?
     

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  2. Huffydavidson

    Huffydavidson STREETRACER/MANUFACTURER

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    Pull the jug off and see if the ring are not broken. Then check the piston & wrist pin for play. Then check the connecting rod for playing as well up and down . If the bottom connecting rod bearing have play, its shot & done .
     
    #2 Huffydavidson, Aug 29, 2013
    Last edited: Aug 29, 2013
  3. MotorBicycleRacing

    MotorBicycleRacing Active Member

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    The damage is from your needle bearing coming apart.
    Probably the upper one on the piston.

    What motors and where have you been buying them?
     
  4. Scott.D.Lang

    Scott.D.Lang Member

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    not looking good. with the miles you are rideing at one time Id say if you dont mind a auto clutch go with a 4 stroke. That said though if you like 2 strokes like I do build you a balanced dax motor. The lack of vibs and power diffrence will make you smile big time.
     
  5. Huffydavidson

    Huffydavidson STREETRACER/MANUFACTURER

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    What ever do mean Scott? The lack of power? That's nothing to smile about.
     
  6. Mike B

    Mike B New Member

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    Also looks like 3 of your head studs are snapped off at the head.

    Yup, your motor is toast.

    Bolt on the other one and hope for the best.
     
  7. glennbo

    glennbo Member

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    get a real motor go 4 stroke youl spend more time riding and less money fixing
     
  8. mapbike

    mapbike Active Member

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    I think what he meant was.... the lack of vibs and increased power will make him smile..... this has been my experience with my dax balanced lower....... cant wait to get my hands on a couple more.
     
    #8 mapbike, Aug 29, 2013
    Last edited: Aug 30, 2013
  9. mapbike

    mapbike Active Member

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    Do them right amd the fixing is very seldom..... and besides you take all the fun out of it if you cant tinker with them a little........lol!

    A good four strome is a darn reliable set up though..... you are right about that. All the good ones I've seen are custom builds.
     
  10. Easy Rider

    Easy Rider Santa Cruz Scooter Works

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    Wow! That's 4 1/2 weeks old?
    I agree in Neil. It looks like your wrist pin Bering blew up and recommend using a better two cycle oil that doesn't leave so much build up.
     
  11. Toadmund

    Toadmund New Member

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    My lower connecting rod bearing went and sent bearing needles up into the cylinder and piston ruining both.
    This engine vibrated a lot at WOT, so much I could not see a thing in my rear view mirror..

    My new motor (not a LEB or BFG) which is the cheapest I could find on ebay is smooth as silk at WOT, and my mirror shows a perfect image of all that stuff behind me.
     
  12. stinky

    stinky New Member

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    Dude watch my video s !!!

    http://www.youtube.com/watch?v=uyj4kvf7xck

    OIL YOU HEAD BOLTS then take off the head!!! The rust fell off of mine, but i think there was definetely some in there!!! Clean it out!! Don't do what I did and blow on it!! Dont move the motor at all. Hope that it is at top and going down. that way when you put oil and draw it down any rust you missed sticks to side.
    Use a vaccumn!! I got some stuck in my ring, but got it clear after oiling it out.
     

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