Vibration Micargi

Discussion in 'General Questions' started by Rockjaw, Aug 31, 2014.

  1. Rockjaw

    Rockjaw Member

    I have to do something with this bike..it still vibrates my feet until my teeth want to fall out...ive replaced CDI ..i also read on jaguars site about making the piston lighter...any advice on that? anyone know if i can just buy a piston instead of drilling holes and changing the pin?
    RJ
     

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  2. crassius

    crassius Well-Known Member

    hard to tell from the pic how the engine is mounted, but I'd lift the barrel a bit so I could see the crank

    if it is old style crank, then I'd spend a $100 to put a new motor with balanced crank in it and use the old motor for something else

    in case it is a balanced crank, there will be much trial & error to see if there is some other mount that will dampen the vibration
     
  3. jaguar

    jaguar Well-Known Member

    get the titanium wrist pin and a Jaguar CDI for a smooth ride
     
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  4. butre

    butre Well-Known Member

    there's no reason for a good engine to be vibrating so badly unless you're using rubber mounts or the mounts just aren't tight enough.

    you've probably gotten a lemon engine. it happens, from some dealers more often than others.
     
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  5. Rockjaw

    Rockjaw Member

    yeah i think so too...(lemon engine) but the engine mounts have no rubber i took them away...vibrates like mad....i may buy an engine from sunfiremotors.com
     
  6. jaguar

    jaguar Well-Known Member

    all these chinese engines are lemons.
    they put them together with the cheapest available parts and didn't take time to balance them.
    I dare anyone who hasn't modded their engine to be more balanced to tell me with a straight face that they can see out of their rear view mirror above 4000 rpm.
    (Now I expect someone to outright lie. Humans do that to protect their fragile egos. They will do anything but admit the truth.)
    Don't buy another engine because it too will vibrate! Fix the one you have!
     
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  7. Timbone

    Timbone Active Member

    My advice: don't give up! Try different approaches!

    At one point, the rear metal block support wouldn't hold tightly because the left rear motor mount stud sheared off clean and I could never get it out. I used a block of wood as a replacement and wedged it in tight with a long bolt and a clamp I fashioned. The wooden support made a noticeable difference at muffling vibration.

    If you aren't using rubber buffers then maybe you should try them.

    Another thing: try adding an extra clamp onto the seat tube. I've used pipe support clamps that you can get in the plumbing dept at Lowe's. 1", 1 1/2", or 2" depending upon how tight the motor is to the seat tube. Use some nylok nuts to grab onto a long bolt screwed thru the clutch cover on the right side and snag the long bolt that passes thru the sprocket cover on the left side.

    Unless you have an engine defect, any little change could make all the difference.

    Good luck! That bike looks too good to just be sitting around!
     
  8. Rockjaw

    Rockjaw Member

    awesome thanks all..yeah the bike is a nice bike ..i like it..but i always grab other bikes to head to the store..unless i feel like having my teeth rattled.

    I tried rubber..everyone said to remove it because its better if the motor is clamped tighter to metal. I will try the the pipe support clamp tmrw..as well as other things..wont stop til i get this sucker to calm down
     
  9. HeadSmess

    HeadSmess Well-Known Member

    im guessing timbone came the closest...there is, imho, a major lack of engine support here, causing the issue.

    that lil dangly bit, that creates the front motor mount...where does its other end join up? nowhere. left dangling in the breeze. hang a ruler off the edge of the table and give it a wack...TWANG. exactly whats happening here...the things just going to vibrate until the other end is secured. another analogy? your motor is sitting on the end of the springboard, contemplating a triple backflip and half turn into the swimming pool... its called a "clamped cantilever" and theres whole books available that are dedicated to describing the way they vibrate...

    you tried the wizz bang, over hyped CDI modification...did it do anything? no. or you wouldnt be here, posting. so why would balancing or lightening anything make any difference? sure, throw money at it. still wont fix that glaring design fault inherent in the frame.

    you cant balance a single cylinder. can reduce the severity to some degree, but what you remove from the up and down movement of the piston, will just appear as a rotating mass on the crankshaft(that acts in all directions as the crank revolves...so its up, down, forwards, backwards, and all points in between). so you lighten the shaft to compensate, and now the pistons back to its up and down movement...so you lighten that, ad nauseum... at some point youre going to run out of engine!

    save your money. get the engine mount attached at BOTH ENDS. how? thats your concern :p

    "but thats how they sell them"... i assure you, everyone else that has a frame with an engine mount like that is ALSO getting buzzed around, titanium gudgeon pins not withstanding.


    all pistons are the same...give or take. drilling holes just reduces strength. really good idea when they accelerate and decelerate a few hundred times a second :rolleyes:


    oh, it may just be my "fragile ego" but according to my tach..im happily hitting 8000 rpm and still using my rearview... and this current engines so far, "stock"... there are definite sweet spots in the rpm range, i wont argue with that. its the nature of ANY rotating part, to have "critical speeds" where harmonics and resonance can increase to the point of failure. certain heavy machinery needs to be accelerated very carefully past such speeds... watch something as "round" as a bench grinder slow down ;) theres always a point where it tries to shake the whole shed to pieces! THAT is the critical speed, and running it at that RPM will cause it to explode!
     
    Last edited: Sep 1, 2014
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  10. butre

    butre Well-Known Member

    I can peg wide open with or without load and still use my rearview, the only "balancing" I've done is a titanium wrist pin.

    you'd be amazed how much glass I've broken because my bench grinder shook it off the table
     
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  11. HeadSmess

    HeadSmess Well-Known Member

    no. no, i wouldnt :p

    been there, done that...we never learn, do we? :jester:

    how much alcohol has been wasted due to a vibrating bench! oh NO!!!!!


    now, i wouldnt be drinking while working would i? :jester:
     
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  12. jaguar

    jaguar Well-Known Member

    the lighter titanium wrist pin makes a big difference indeed.
     
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  13. Rockjaw

    Rockjaw Member

    Here is a close up of how its mounted..the other pic was a lil far away..the bike also has a 56 tooth maniac sprocket...so it revs up quick..im just now seeing that on the exhaust pipe ..one of the studs is a lil bit stripped...so the pipe may not be on very tight ..that may be 1 reason why its vibrating..but could be other reasons as well.
     

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  14. butre

    butre Well-Known Member

    is the muffler actually secured to anything or is it just left to flop about all it wants?
     
  15. Rockjaw

    Rockjaw Member

    I was thinking that too..its one of those silly poopoo pipes..it not secured to anything..it seems like its on tight but when engine is revved up..im sure it may be causeing trouble
     

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  16. butre

    butre Well-Known Member

    yeah that pipe is going to break off if you don't secure it to anything. it might be a pretty big source of the vibrations too
     
  17. HeadSmess

    HeadSmess Well-Known Member

    i can see the engine mount clearly. its only supported at one end. continue it through to the top or down tube, so its rigid.

    and the exhaust weighs what...1.5 kg? 3 lb? more? lot of weight to have just dangling in the breeze :eek:

    same deal...its just a springboard, buzzing away.

    two obvious faults with (possibly) simple remedies.


    now i see it better, i assume you inserted that front mount, they dont come like that?
     
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  18. crassius

    crassius Well-Known Member

    not much you can do with that mount except tie down that muffler and experiment with shifting things around a 1/4 inch at a time to find a sweet spot (unless you have the old style crank which can't be stopped from vibing at high Rs)
     
  19. Fabian

    Fabian Well-Known Member

    :iagree: if the engine isn't firmly affixed to the frame it will appear to vibrate like nothing else.
    A good part of your vibration issues stem from the front engine mount, built into the frame design. It has no support so can flex. This will massively increase vibration as the engine bounces around on the front mounting tube, which will effectively act as a spring; amplifying vibration.
     
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  20. Rockjaw

    Rockjaw Member

    ok cool..im gonna try using a muffler holder..the one that came with an engine kit...to support that pipe..thats next step ;)

    yes i did have the stem welded on there to mount engine
     
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