Bigger studs on my second engine.

Discussion in 'Motorized Bicycle General Discussion' started by Nomad, Aug 28, 2008.

  1. Nomad

    Nomad New Member

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    I bought a second China engine and posted a thread about a hole in the "jug".. I was going to try to remove the stud before using JB weld for repair. When I removed the acorn head nut i noticed that the stud on this engine is much thicker that the 66 cc I got. This one is supposedly a 80cc, but I suspect it's really a 66cc... anyone else notice larger studs on one engine from another?....
     
  2. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    Some have 6mm and some have 8mm. Seems to be no rhyme or reason.
     
  3. stude13

    stude13 New Member

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    change out all hardware and use red and blue losktite. a dremel is very useful.
     
  4. Nomad

    Nomad New Member

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    I don't understand your post.
     
  5. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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  6. heyscuba

    heyscuba New Member

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    dremel for what when replacing bolts,...?
     
  7. oldtimer54

    oldtimer54 Member

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    What there trying to say is when you have the head and jug off use the dremel to clean up the castings match ports and polish stuff. Lots of great info here just search for port matching.
     
  8. heyscuba

    heyscuba New Member

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    ok,.. hey I'm 51, I'm ok with tools and motors a little, basically on cars brakes and oil change and general maintenance, I did do a ball joint on my Explorer last year "Whoop Whoop!" and I mess with a chainsaw, weed whacker, mower now and then a garage mechanic, but usually just check for fuel movement and spark, I don't know all the terms and methods spoken of here,... so starting from the top, the head I'm guessing is the top, where the plug is, and it bolts to the 'block',...? which is bolted to the crank case,../ are these the 3 main components to this engine,...?
    I'm on this thread because when I went to take the head off to look at the top of my piston on of the bolts rods (threaded on both ends) came out with the acorn nut, so first I had to vice grip the rods center and work the nut off, then to get the rod back into the bottom of the engine I had to use the vice grips again to get it down in there, this did not go smoothly,... I couldn't hold the rod the way it was so I ground down some flat spots just below the threads so the vice grip would hold and then I got it to thread down in there, now I can use the acorn nut, but I'm thinking this is a situation I should fix, this is a new engine (1st build) and only had been run a few minutes,...
    should I work that bolt back out now and replace it and the rest of them or leave it till something happens,...?
    and I guess I'll have to order the bolts, or can I pick those up or have them made for cheap, I live in St. Louis so many,...


    as for the dremel, you guys means to have a wire wheel on it for some clean up huh,...!
    I'll search matching ports,... ( I think I know what it means though,.)

    hey thanks,....!!!
     
  9. oldtimer54

    oldtimer54 Member

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    The castings are very ruff on these motors so most of the time there are flanges of metal from poor casting in the ports so we like to clean that stuff out. We use the dremel with the right size grinding weels to clean stuff like that up. Youll see what I mean its all been gone over many times here just search and youll find it all out.
     
  10. heyscuba

    heyscuba New Member

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    ok,...
    the castings are the edges of the metal where it was pulled away from a mold and there are sharp edges,...?
    and the ports are the 2 opening I guess, 1 coming in from the carb side and the other leading out to the exhaust,...? and just clean these openings up and smooth them out with a dremel,
    this I assume is done with the block off the motor and the piton just hanging there for the time being,...? or do you just pop the head off and push the piston down and put a rag or something down in there and make sure you don't get filings or metal dust down in there,..?
    this is the stuff we don't know, it's pretty much, "smooth out your port holes with a dremel"

    again, thanks,
    just trying to learn,.....
     
  11. kicking

    kicking New Member

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    I taped all mine to 1/4 inch .... neber have problems now
     
  12. earl.k

    earl.k New Member

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    66 and 80cc chines two stroke motors are the same thing. 66cc is 80cc i dont know why? but they are sold as 66/80cc.. or they have the smaller 48cc. and i got two shyhawk kits in 2010. and they had different head bolt sizes. and hardware? different shipments i guess...they where only made 5 or so months apart.
     

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