Thoughts on silicone in handle bars and in frame of bike to reduce vibration...

Discussion in '2-Stroke Engines' started by Bike916, Aug 2, 2009.

  1. Bike916

    Bike916 New Member

    So I bought 3 Powerking 80cc motors. 2 silver, 1 black.

    The first install, the silver engine, the bike rides nice, but a lot of vibration at high speeds.

    The second install, the black one, bike rides nice and real smooth even at full throttle.

    3rd bike, still in progress so update shortly.

    I installed engines exactly the same on both, but the vibration on the first one is killing me because i want to figure out why. I've heard silicone can help reduce vibration. Has anyone tried this? Has anyone did the whole lead in the handle bar thing? How is that done? Maybe I would do that.

  2. rubber handle bar grips between mounts and frame will get rid of 90% of all the vibrations.
  3. Bike916

    Bike916 New Member

    Well I had some rubber in all the mounts intially didnt do much. So on my 2nd build did not use rubber, no vibration at all. So on my first build I took out the rubber and still the same vibration. So I tend to think rubber makes little to no difference.
  4. fetor56

    fetor56 Guest

    With my motorbike i put sand in the did make an improvement but not as much as i hoped for.
  5. HoughMade

    HoughMade Guest

    Silicone is one way to go- not a bad idea. Another idea is lead shotgun shot that can be bought in bulk from a good sporting goods store that stocks reloading supplies. A silicone capper in each end would hold the stuff in.
  6. loquin

    loquin Active Member

    By increasing the mass in the system, you change the resonant frequency, which helps to de-tune the vibrations.
  7. arceeguy

    arceeguy Active Member

    I think the best way to reduce vibration is to start at the motor mounts. This is how automakers reduce vibration in today's 4 cylinder cars. If a mount goes bad in a car, the engine will literally jingle your keys in the ignition at idle, and vibrate the heck out of your rear view mirror on the highway.

    My smoothest HT bikes are the ones where I have to rig a custom mounts to accomodate large frames. I put rubber hose over the U-bolt and rubber isolators on everything else as spacers, but they do a great job of isolating the engine from the frame. These bikes can scream along at 30 mph without numbing body parts.

    The ones that tend to vibrate the most are the diamond frame bikes where the engine fits perfectly. Great for a quick install, bad for your nutz.
  8. i could'nt have said it anybetter than arceeguy,thats why im using a custom from mount and thick rubber between my mounts and frame. I also have rubber peddals from a exercise bike and i wear boots. 0 Vibrations at any speed , even at 30mph+.
  9. Just_Gasit

    Just_Gasit Member

    I put some rubber hose inside the handle bars and another one in the seat post tube. It helped a bit but not a total cure. I tried rubber in the motor mounts, I have less vibes mounted solid, others say it helps. Currently, my 66cc has vibes but they are liveable and not nearly as bad as the first mounting. You might try just re-mounting your kit making sure the cast mounts fit the tubes (file with a half round file if not) and that the mounts sit into the tubes best possible. It helped mine the most.
  10. graucho

    graucho Active Member

    As far as handlebars go I use expanding foam insulation. Light weight, trim off the excess after it oozes out after drying. As for the inside frame tube, I dont use anything. A matter of fact I make sure I have weep holes for moisture escape, and so I dont create a bomb when welding with it. I also agree with the motor mount idea but I have to straighten/align my engine every 300 mi or so. Tried 3 different materials but still shifts after time.
  11. I have a custom front mount and use rubber handlebar grips cut in half between my mounts and frame.
    My mounts are tight and bolts are double nutted plus i have a muffler strap to hold muffler and engine to frame.
    i never have to straighten or alighn nothing.
  12. bmc_az

    bmc_az New Member


    I used 3/4 by 3" bolts screwed into the handle bar to create bar end weights.
    kills 90% of bar vib's. They made generic bar end weights in the past but i couldn't find any. So....

  13. juliman

    juliman Member

    what about silicon on the motor mounts... or silicon and rubber =-)
  14. Al.Fisherman

    Al.Fisherman Active Member

    If anyone has vibration that bad, the engine is not mounted to the frame correctly. My first build with engine #1 vibrated so bad that my hands tingled for 30 minutes after riding. I took that SAME engine and mounted it on another frame (first one cracked in two...cause....drillinbg a hole in the tube), mounted engine to frame, not frame to engine and can ride for hours without undue vibration. Find the cause, fix it, don't try to hide it. Three other builds with same type engine and no vibration problems. Proper mounting is the #1 key for the smoothest ride. Number 2 is true running wheels and tires. I NEVER start a build that I don't first true up the wheels. This should be done before the engine is ever taken out of the box. I don't care if the bike is new or used.
    Last edited: Jun 1, 2010
  15. Fabian

    Fabian Well-Known Member

    I have a terrific answer to the question posed in the thread but it would only get me banned :grin5:
  16. Zev0

    Zev0 Member

    Well then, by all means, let's hear your answer.
  17. professor

    professor Active Member

    Zev- that was a good one. But I like Fabian, am curious though.
    I'm with Al on this one, the handlebars are just ringing in sympathy with the engine vibes.
  18. Fabian

    Fabian Well-Known Member


    Surely now, you wouldn't want to see me banned :whistling:
    I need to invest time in a suitable protege before getting booted :jester:

  19. Vistaman73

    Vistaman73 Member

    When I had my engine, it vibrated like crazy. I almost had to wear a diaper... After some chatter on the web, I found that it was very possible I had a bad crank. So I tore it apart only to find I had the Devil's Engine! Half the stuff wouldnt come apart and I found that the crank spun like a banana. The large flat head screw on the crank gear spun in a cone shape. LOL. So I sold it a few months ago and the last ~4 months have been very, well, flat. :( Right now, Rich is bulding me a hand made engine with ported cylinder and those nice bearings. Can't wait to get it. I told you that to tell yall this. These engines are like snowflakes, not one is the same as another. The first one may be less "balanced" than the other. When you have multiple MBs, one fix might not work on all the bikes. Keep that in mind when diagnosing these bikes. "This one doesnt run the same as my last one" Well, if it did, then that would be a miracle. LOL