I REALLY need more power and speed

Discussion in 'Motorized Bicycle General Discussion' started by Sheriff John, May 28, 2011.

  1. Sheriff John

    Sheriff John New Member

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    I got a motor-bicycle and home built it. I haven't ever rode it because of the low power, instead i use my goped. I LOVE riding it and id dont want to sell it, but i just NEED to up the anti..shft.
     
  2. Skarrd

    Skarrd Member

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    how much power are you looking to get?
     
  3. Sheriff John

    Sheriff John New Member

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    as much as i can. 80cc motor
     
  4. Skarrd

    Skarrd Member

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    well one thing you can do to free up some power is to pop the intake pipe off, rotate the piston to top dead center, and check if the skirt is still covering the port, use a fine tipped shapie to mark where it still is, then take the cylinder off and cut out said area of piston.

    also an expansion chamber, correct oil mix and carb tuning help alot!


    remember, 24:1 1st gallon, 32:1 there after.
     
  5. Sheriff John

    Sheriff John New Member

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    so i cut the piston with a dremel? And do i do this to the entire part or the skirt that is showing?
     
  6. Skarrd

    Skarrd Member

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  7. bairdco

    bairdco a guy who makes cool bikes

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    if you really are a sheriff in san diego,VC Section 23135 states that it's illegal to modify a motorized bicycle to go over 30mph. :)


    (sorry, couldn't resist...;))
     
  8. spad4me

    spad4me New Member

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    Post pictures if possible.
    You will not get a goped quality engine from a china girl kit.
    The best you will get is a goped type performance with a shift kit. And engine mods, plus a tuned pipe.
    Sick Bike Parts LLC - Performance parts for your motorized bicycle

    Count on spending more than the china girl kit cost.

    I use a gp460 with a scooterguy mount. A 5 to 1 reduction transmission feeding the sick bike parts front crank setup.
    40 to one in first all the way to no more oomph left in the 460 in seventh gear.


    The Chinese engines do not measure cc displacement as you or I would. An 80 cc is a 66 cc.
    I recently bought a 40 cc engine that turns out to be a 24 cc.
    Good price but I wont buy from them again.
     
    #8 spad4me, May 28, 2011
    Last edited: May 28, 2011
  9. Sheriff John

    Sheriff John New Member

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    Ok, so I decided to do two things.

    1. The piston skirt mod
    2. I want toopen the exhaust port. How much do I do it?

    If I do both of these, what will I gain in performance?
     
  10. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    You should get a little bit more, but nothing that'll blow your socks off. Add a tuned pipe and it'll help a lot more.

    dnut
     
  11. Skarrd

    Skarrd Member

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    really though, if you want serious power... get a morini. you'll end up spending the same on hop up parts for the china girl (and replacement parts)



    kinda wished i had gone that route now, lol.
     

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