need help with the head and cylinder bigtime!!

Discussion in '2-Stroke Engines' started by daveet, Jul 2, 2016.

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  1. daveet

    daveet Guest

    Just bought cylinder and head from boy goes fast! Looked the same but its not! I took 3 pictures but cannot fig out how to put them on here! I got ripped off the 4 head bolts are twice as small as the others and nothing is the same! Have not got a clue and need help big time! My man crassius where you at?

  2. Steve Best

    Steve Best Well-Known Member

    Sounds like you bought a 48cc cylinder for a 66cc engine?
    You need the right parts...

  3. butre

    butre Well-Known Member

    can you post a link to the item you ordered?
  4. jaguar

    jaguar Well-Known Member

    call the supplier
  5. crassius

    crassius Well-Known Member

    yes, without a pic, I'm guessing you got a 49cc head, but it may be the strange version of 80cc that uses 6mm studs

    either way, it is easiest to get the right one - the 49cc can not be made to fit, but the 6mm 80cc might be made to fit with a lot of effort
  6. 45u

    45u Active Member

    49cc run 6mm cylinder studs other run 8mm studs.
  7. Frankfort MB's

    Frankfort MB's Well-Known Member

    There are some 6mm studded 80ccs
  8. 45u

    45u Active Member

    If you look up cylinder studs they say 6mm 49cc and for all others run 8mm. There is not any one that makes a 80cc even thaw they call them that the biggest is only 69. something CC. Has anyone else seen 6mm studs on anything bigger then 49cc? Now I think and not sure there might be some a LITTLE bigger maybe correct me if I am wrong but nothing with 47mm bore with 6mm.
    Last edited: Jul 7, 2016
  9. butre

    butre Well-Known Member

    I've seen 6mm studs on 66cc engines. it's mostly older ones that stay overseas, as far as I know all the ones that make it to the states have 8mm studs
  10. gary55

    gary55 Well-Known Member

    Yep boy go fast still sells 66cc 6mm top ends oops. prob. need the 8mm.
    Last edited: Jul 10, 2016
  11. Malin

    Malin New Member

    Hello! while im here and i found this thread and i have a quick question, How many pounds should i set my torsion wrench to for the 4 head bolts when replacung the head? I just bought a new higher compression head from Bicycle Motor Works and I don't know what a good tension on the head is.
  12. gary55

    gary55 Well-Known Member

    I set mine at 162 in. lbs. if you are using a ft. lb. wrench 13.5. That is on 8mm head studs.
  13. Malin

    Malin New Member

    Thanks so Much!!!
  14. gary55

    gary55 Well-Known Member

    Boy go fast store on e bay. visit store search 66 / 80 cc 6mm bottom end. At one time they were made, and the complete motors are still available though god only knows why anyone would opt for the weaker design.