dampening idea

Discussion in 'Motorized Bicycle General Discussion' started by Tim Mills, Oct 23, 2009.

  1. Tim Mills

    Tim Mills New Member

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    Hello everybody i will be starting my new build soon an have already gotten some great ideas from you guys. I thought of this idea the other day. i know these engines cause alot of vibration so i was thinking expando foam in the frame? My bike alraeady had holes made to run wires for taillight and headlight so i could actually fill most of the frame with this foam. Let me know what you guys think
     
  2. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    That sounds interesting... but I don't know if it will deaden the vibes tho?
     
  3. pedro5189

    pedro5189 New Member

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    balance the crank
     
  4. philymitch

    philymitch New Member

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    I have used expanda foam in my frame and my handle bars. using the foam in the handle bars reduced a lot of the vibrations in the bars. filling the frame with expanda foam really helped with vibs and noise from the motor. the foam will absorb alot of things you will be surprised hope this helped you.
     
  5. xlite

    xlite New Member

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    Two of the guys I built bikes for tried filling handlebars with Great Stuff. They both raved about the improvement but I saw no difference at all. My buddy who also rides these could not tell which bike had the foam in it during a blind test. Another fellow filled his tube with sand and it did make a difference.

    The almost non existant mass of foam should not have any significant effect on vibrations.
     
    #5 xlite, Oct 23, 2009
    Last edited: Oct 23, 2009
  6. skjjoe

    skjjoe Member

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    be very careful not to get it in the bottom bracket that stuff is hard to get off.And i have heard of the stuff expanding into the bb and locking up the bearings.
     
  7. BarelyAWake

    BarelyAWake New Member

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    Sprung seat an gel grips, yer only hope lol
     
  8. bandito

    bandito New Member

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    Youd be surprised how well a $20 suspension seat post helps and I weigh 215. I think GOD created gel grips just for folks on 2 wheels. I know theres better seats out there but Im satisfied with mine its leather and wide for the rear plus it has good padding.
     
  9. philymitch

    philymitch New Member

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    i did my frame when it was being built so all excess was cut off. no problems with my bearings. i say do it you wont regret it.
     
  10. Tim Mills

    Tim Mills New Member

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    Hey guys thanks for your quick responses i will probably try all your suggestions and since i have to break my bike down to send it home i will jus be patient, paint it an all that good stuff i would rather take my time the first time so i will have more time to ride thanks guys .flg.
     
  11. 42blue15

    42blue15 New Member

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    Somebody posted about the problem of the foam getting into the bottom bracket on motoredbikes.com.

    I have tried to use this foam for filling other purposes and found that it does not fill nearly as consistently as you'd think.

    What I would suggest would be to use some urethane sheet in your motor mounts somehow. It is risky to try to use rubber for motor mounts, because the fuel/oil spilled on them may chemically attack and degrade the rubber. Urethane is far more resistant to this problem. Stick to the harder durometers--60-70 or more.

    Sorbothane is a premium type of urethane designed to absorb vibrations. It dampens much better than any other urethane or rubber out there. In the USA, Sorbothane (as well as plain sheets of urethane) can be ordered from McMaster-Carr.
    ~
     
  12. bandito

    bandito New Member

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    When mechanical engineers want to isolate vibrations they try to reduce the causes 1st, when that isnt possible due to the nature of the beast then they try to isolate the vibrations. I wonder why engine mounts on cars use rubber? Nuclear powered subs have almost every thing in them hanging or mounted by rubber mounts or other designs to minimize vibration travel. I wonder why they use rubber mounts instead of foam filled encapsulated hangars. Maybe automotive engineers havnt thought of foam yet.
     
  13. xlite

    xlite New Member

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    Military has a propensity towards things that WORK.
     
  14. BarelyAWake

    BarelyAWake New Member

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    erm... mostly :p

    But we'll just leave THAT 'un alone laff
     
  15. Cabinfever1977

    Cabinfever1977 New Member

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    i used rubber under my mounts and taped them tight to the frame with black tape.
    is still holding up and not wearing down and there is no engine movement.
     
  16. diceman2004

    diceman2004 New Member

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    all the expanding foam i,ve seen gets hard when its cured ( harder than styro foam ) by harder i mean more brittle .

    sorry if i sound so negative , but i don,t see how 5 ounces of brittle expanding foam can possibly make a difference that you can actually feel .

    i think you would have better results by filling the ends of your handle bars with play-doh
     
  17. Kevlarr

    Kevlarr New Member

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    Pffft... the motor mounts and trans mount in my Toy truck are solid steel. :p
     

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    #17 Kevlarr, Oct 25, 2009
    Last edited: Oct 25, 2009
  18. GearNut

    GearNut Active Member

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    I think you lost your left front wheel.....:p
     
  19. GearNut

    GearNut Active Member

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    A few years back I saw "liquid bar snake" sold in Harley aftermarket catalogs. It was some sort of epoxy rubber that you poured into the handlebars to reduce the infamous Harley hand numbing vibrations. I have only heard that it works, never a complaint that it does not. I haven't seen it for years. I wonder if it is still available?
     
  20. BarelyAWake

    BarelyAWake New Member

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    Nice Kevlarr :D Toys r ossum ;)
     

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