OzVMX Forum

Clubroom => Tech Talk => Topic started by: Noel on April 08, 2009, 08:27:47 am

Title: Taming vibration through handle bars.
Post by: Noel on April 08, 2009, 08:27:47 am

Any body got some good ideas on this.
I have a CZ 360 with the original steel Handle bars with welded on perches,
after a bout 2 laps the vibration through the throttle side handle bar sends my right hand
numb which makes throttle and brake control a bit dicey .
the frequency of the vibration also negates the return spring pull which is quite strong when the engine is stopped.
any Ideas on a cure for this
Cheers
Noel

Title: Re: Taming vibration through handle bars.
Post by: Bamford#69 on April 08, 2009, 08:43:31 am

HI Noel,
  Iv'e got a 250 and 360 and now no vibration , someone had tightened up worn out ,loose engine mount   bolts , check the mount bolt holes in frame and motor also, they may be elongated . are the steel sleeves in place .
  Has this vibration just appeared or
  has it been there for since you got the bike,or
  have you just rebuilt the motor,
  have you had this motor running without a vibration.

Title: Re: Taming vibration through handle bars.
Post by: LWC82PE on April 08, 2009, 08:49:49 am

you can get weights or plugs that go inside the bars ends to stop this vibration.

Title: Re: Taming vibration through handle bars.
Post by: Bamford#69 on April 08, 2009, 08:59:11 am

Hi Noel,
one more; is the vibration more severe at idle , or worse at high revs?

Title: Re: Taming vibration through handle bars.
Post by: 666 on April 08, 2009, 09:46:17 am

Wear thicker gloves, or vibration proof hand grips, ear plugs will be a good idea too,  and take a large cardboard box with you to the next race day for the bits that fall off or out.
L O L

Title: Re: Taming vibration through handle bars.
Post by: Nathan S on April 08, 2009, 10:02:43 am

Alloy bars are the simplest way to reduce it. They'll also take out some of the 'sting' if you bottom it out harshly over a jump.

The newer style 'fat bars' are even better, but are a fashion crime - particularly on a short travel bike.

Title: Re: Taming vibration through handle bars.
Post by: Noel on April 08, 2009, 07:06:02 pm

Thanks for feed back,
I was thinking Ally bars may help also thought of filling bars with resin or lead ,expanding foam, etc.

Jikov, had bike for about 9 months ,always had this vibration, fine at idle ,
I think it  is most noticeable mid revs.
did check tightness of engine mounts but have not removed bolts to check for worn hole or bolts.
will do so.
Cheers
Noel

Title: Re: Taming vibration through handle bars.
Post by: Viper79 on April 08, 2009, 07:27:29 pm

You could also try these, I have them in my CRF450 and they seem to make a difference.

http://www.fasstco.com/products/insert.shtml

Title: Re: Taming vibration through handle bars.
Post by: HL400 on April 08, 2009, 07:44:37 pm

Hi Noel I would be looking at the flywheel, it may be out of ballance,  HL

Title: Re: Taming vibration through handle bars.
Post by: Bamford#69 on April 08, 2009, 08:29:56 pm

Hi
If the bike has had the vibration since you have had it,it might be a simple as the crankshaft not in balance ,the early crankshafts are full circle flywheels, the later model "pork chop" crank rev faster but are a bit lighter, the combination of aftermarket pistons, the wrong model ignition flywheel , is possible , also if it has been assembled roughly , hammered together without heating the cases, it may have altered the "alignment" of the crankshaft cheeks.
A lot of CZ internals are the "same" ,that is they will fill the hole , but its the  combination of those bits from the other different models that make for better motors     

Title: Re: Taming vibration through handle bars.
Post by: albrid-3 on April 08, 2009, 09:26:11 pm

Cut round peices of rubber and place them between the fins.