dynamic crankshaft balancing

Discussion in 'Motorized Bicycle General Discussion' started by metalliatic, May 22, 2010.

  1. metalliatic

    metalliatic New Member

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    got my foureasy balanced crank today. hopfully will have it installed this weekend. i will let you know what i think.
     
  2. 5446

    5446 New Member

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    cool! what I want to know is if it helps getting you up hills?
     
  3. foureasy

    foureasy New Member

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    @emdude
    yes
    yes
    yes

    @metalliatic
    remember, no hammers :)
     
  4. metalliatic

    metalliatic New Member

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    got the motor together last night. the crank went in easy. the clutch shaft was a problem. one of the bearings come out of the motor and stayed on the clutch shaft when i disassembled it. so getting that bearing back in the crank case was a pain. now i gotta get the motor swaped out on my bike. i have a shift kit on it so its going to take alittle longer. hopefully i can find the time to do it this weekend.
     
  5. 5446

    5446 New Member

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    let us know if it gives you any more bottom end. Thanks
     
  6. nitroscope8

    nitroscope8 New Member

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    bump for answer~!
     
  7. msrfan

    msrfan Active Member

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    Hi foureasy. I have several motors that shake themselves to death. Do I sent the crank to you for the treatment? Also, do you have to split the crank?
     
  8. foureasy

    foureasy New Member

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    Yes and yes. Or you can tell me what number is cast into the connecting rod.
     
  9. Whiplash

    Whiplash New Member

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    Can you do the RAW motor crank as well? I am very interested in your current mods to the engine as well! I am planning a build up and would be pleased with 6hp if that's doable without killing reliability. I actually am VERY skilled at porting 4 cycle engines (I actually used to build Indy 500 Race engines for Nissan, as well as MANY other forms of racing, I literally have 1000's of porting hours under my belt), but have never attempted a 2 stroke. Any tips? I know I will need to raise and slightly widen the exhaust port, but I am not too sure what to do with the transfers and such other than just clean them up...

    P.S. What carb and exhaust are you using?

    Thanks a TON!! I am new to this bike stuff but its really FUN! I am hoping to get 50MPH with a shift kit and really good acceleration and off road climbing power!dnut

    Thanks for the help!
     
  10. foureasy

    foureasy New Member

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    any crank.
    you have to put a degree wheel on to properly time and port a motor.
    im using a hand made pipe and a 24mm flatslide mikuni
     
  11. Whiplash

    Whiplash New Member

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    OK, thanks. I can do that, I always wondered how they got the timing. It sounds like you do it similar to degreeing in a camshaft?? Do you have any tips for a novice to get it running good? How about a quick and dirty on the proper timing for something like I am trying to do?

    Thanks!!!
     
  12. Thud

    Thud New Member

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    Hey Whiplash,
    (you givin up on the lectrics? ) Grahm bell gives an excelent tutorial on the math formulas for small piston port engines. Lots of working examples. Nothing on crank ballanceing though. But every thing else is in there. Google will get you a bunch of places for a free download.

    Has any one found a better rod for rebuilding these with? or better said a good big end bearing? I wll research for a yz60 or like that con rod. I have machine capability so resizing for a different crank pin is not a huge problem.

    Just fishin for info.
    T
    http://www.kreidler.nl/artikelen/performance-tuning-graham-bell/performance-tuning-graham-bell.pdf
     
    #32 Thud, Sep 28, 2010
    Last edited: Sep 28, 2010
  13. Whiplash

    Whiplash New Member

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    Nah just like the range of the gas!!
     
  14. foureasy

    foureasy New Member

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    155-160 exh
    116-118 transfers
     
  15. foureasy

    foureasy New Member

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    114 intake
    get a moped expansion chamber and make it fit without making it any shorter.
    buy a real dellorto 16/16 sha carburetor.

    @thud
    i havent had any problems with any of the short rods, but i do have some better bearings for both ends. $15 for the big end and $10 for the small
     
  16. Goat Herder

    Goat Herder Gutter Rider

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    So you shimmed that last jug at 6.75mm or did you change it?
    Also are the replacement bearings bushings at the piston side?
     
  17. Goat Herder

    Goat Herder Gutter Rider

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    I can't stand it I have a collection of China motors to play with. I am going to do a hybrid. This just sounds like a fun project!
     
  18. foureasy

    foureasy New Member

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    Good bearings for both ends.
    Nice! Buy the puch gilardoni and you're set.
     
  19. Whiplash

    Whiplash New Member

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    Hey thanks! So these numbers are opening right? So I would look for the port to just barely open and then that is the timing right? Where do I get the bearings and is there any machining involved? Thanks!!!

    I am anxious to try this!

    I actually considered building my own expansion chamber, and build it with two cones and a straight section in the belly, any idea where would I find the math to figure out the profile? I was just going to try and copy an existing design to get close and then play with it till I got it right, but if you know a good starting point for these little motors I would greatly appreciate it!!

    xct2
     
  20. foureasy

    foureasy New Member

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    Get the bearings from me.
     

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