Eliminating Handlebar Vibration?

[KJDonovan]

I have been reconditioning a 74 Mint 400 and finally have everything dialed in performance wise where I like it.  My only issue is the vibration through the handlebars is killing me.  

Even after a short ride my wrists and knuckles feel like I went 10 rounds punching rocks.[xx(]  So I was curious what works to eliminate this.  I already have some great squishy grips, but I need to do something more.  I did a search here and online, I have seen various things to reduce the vibration, from filling the bars with steel shot to something called a bar snake.  Figured I would ask here, what works and what doesn't.

Thanks,

Kevin


Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner
72 Six Day
74ish Mint 400
74 Hare Scrambler
71 Suzuki TS125
72 Montesa Cota 123

[454MRW]

I have a set of crossbar-less alum/maybe SS. Original vintage bars on my 77 RM370. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1978 KTM 250'S
1975 Can Am 175 TNT 250 conversion
1976-78 125-400 RM's & 79 PE250 Suzuki & 2012 DR650
2007 CR125R Honda
1977 MC250 Maico

[wfopete]

Here is a high dollar, new age solution that is perfect for short travel bikes:  http://twistedengineering.com/



Pete Petrick
175 Jackpiner
Slow but Good

[Jason Rowland]

If the science behind the bar snake is sound, it seems like you could test it cheaply using wax, petroleum jelly, or another compound you could easily blow out or melt out.

[KJDonovan]

Thanks for the responses, I think at this point I will try filling the bars with steel shot to see if that helps, it that does not work I will try filling with melted wax or crayons.  As for the $299 [:0] set of bars, way to pricey for me.

Thanks,

Kevin

Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner
72 Six Day
74ish Mint 400
74 Hare Scrambler
71 Suzuki TS125
72 Montesa Cota 123

[jeff greenberg]

Didn't there used to be hard rubber shim- spacer you could put under the handlebar mount?

[Daniel P. McEntee]

I would make sure that all the engine mounts are tight, and that there is no slop or play in the swing arm and triple clamps. I know you said you were reconditioning this bike, but wouldn't hurt to double check.
  Type at you later,
  Dan McEntee

[firstturn]

KJ,
  I thought I might point out one similar problem a Friend had.  I just loosened all the bolts on the engine and then made them finger tight.  I took several times to tighten the bolts in a pattern from the inside out.  It solved his problem.  Remember the frame is like a tuning fork and if you bind it up it will react with a vibration.  Hope this helps.

Ron Carbaugh

[Jason Rowland]

Upon further contemplation, wax might crack into pieces. Perhaps aloe vera gel, or something along those lines might be better suited to test the theory.  Then at least you'd have a salve available in case you need to soothe those aching palms....

[KJDonovan]

Thanks for the additional responses....

Dan,
Nothing loose or sloppy in triple trees, as part of freshening this bike up I pulled apart the steering head races, made sure all the bearings were there and repacked it with grease and fresh o-rings.  Replaced the needle cages in the swingarm and checked all mounting points on the motor.

Ron,
Great idea, I did not even consider that.  I did make sure everything was tight, but did not consider that something may be binding.  I will try exactly what you recommend, makes perfect sense!

Jeff,
If there is a hard rubber mount for the handlebars, I have never seen one, just metal on metal.

Thanks again guys, I will let you know how I make out.

Kevin
 


Kevin J. Donovan
Foster, Rhode Island
72 Jack Piner
72 Six Day
74ish Mint 400
74 Hare Scrambler
71 Suzuki TS125
72 Montesa Cota 123

[wfopete]

Two more high dollar solutions:

http://www.motorcycle-superstore.com/37414/i/fasst-company-anti-vibration-bar-inserts.aspx

http://www.motorcycle-superstore.com/53759/i/rox-speed-fx-elite-series-anti-vibration-pivot-risers

Pete Petrick
175 Jackpiner
Slow but Good

[Rain Man]

400's do vibrate yeoww!!. I think Mr. Carbaugh  gave some good advice as far as the motor mounting goes. I know on some bikes you have to shim under the motor perch sometimes to keep from twisting the frames or , breaking the motor tabs.  Of course our KTM 's have mounting holes, but if your trying to pull the frame in, one position say .020" ,that bolts doing something else, including trying to hold the motor in the frame.
 Also the cylinder head bolts are prone to loosening up on that big motor.
2c

Raymond
 Down East Pentons

[firstturn]

Thanks Rain Man for reminding me to add when you see space between the frame and engine when you have your bolts hand tight you must put washers in that space.  If you pull the frame in you are messing with the frame harmonics.  Not trying to sound smart here, but I used to have to fix bikes for Honda and a lot of the fixes were via the phone so I had to be up on engineering.  But I am getting old and forgetful.  Thanks Rain Man for the thought.

Ron Carbaugh