Handlebar vibration reduction - bar end weights?

Wine corks fit perfectly but need to be chamfered to get started into the bar. I cut about 1/2 off.

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With no expertise, I'm thinking softer is better for damping action.
IE the softer more flexible the silicone mount the better chance the weight will act as a vibration reducer?
A one piece weight better than shot in a matrix?

Not sure. I’ve read about several methods but each of those was “this is what I did” vs “here’s the three methods I tried and this is the best”.

Bar end weights seem to be helpful so extra mass at the ends shouldn’t be detrimental to the cause. I’d love to do some proper experimentation but trouble is I’m doing this in the middle of winter and won’t be able to test until the springtime and that’s a ways off. I’m thinking after that long a period of time, my interest in trying methods 2 or 3, will have diminished.

Right now the plan is to try the lead shot in silicone (the mushy stuff they make molds and adult toys out of (so I hear)). It should be fairly easy to do. I was originally going to do loose lead shot but Jim’s note about the shot disintegration had me change my mind.

Stay tuned for more posts and pics on my experiment.
 
With no expertise, I'm thinking softer is better for damping action.
IE the softer more flexible the silicone mount the better chance the weight will act as a vibration reducer?
A one piece weight better than shot in a matrix?
Interesting discussion. I'm akinda thinking about how the added mass reduces vibration, and whether as gggGary thinks a flexible mount would help with damping. I'm tending to the opposite view.

Vibration forces shake your handlebar, adding weights damps the vibration. I'm suggesting damping results when the vibration forces try to move a heavier object. If the weight is attached, it is part of the handlebar, but if not attached I'm not sure how it will help. For example, if you put lead shot inside the bar but without it being attached, the vibration forces will still shake the bar just as before. The lead shot will be jiggled around and will eventually grind each other to lead dust. Which leads me to think molten lead poured in and set will be much more effective in damping the vibes? Don't think I've explained that very well . . .

As I write this, just notified about Bosco's post above.
 
Over the years I have used the expandable aerosol foam for sealing around window rough openings, the metal ball deal and
then tried sand. several options to seal the bar ends. silicone ,bar end plugs or the pipe plugs used to protect copper or metal
Pipe in diameters from 1/8" to well over 3". Remove bars Seal one end,stand on sealed end. Pour in sand through a small
funnel and then seal that end. Also these old style cushioned grips have been around forever. Possibly even longer. If you have smallish hands they may not work. But for old arthritic mitts they have been my go to grip for a lot of bikes. 2 stoke and 4 stroke. Price is right as well.
Hope this helps. Belated Happy New Year to all.
https://fortnine.ca/en/emgo-gran-tourismo-cushion-grips
 
its been a long time since I read it

First if the lead pellets are ground down this deformation wont happen unless the lead is absorbing energy as I Se it
most likely vibration energy

If there is a plug sitting tight in the bar .It moves as a response to the vibration excitation
Without the weight in the design has one frequency for resonating with the weight in another design another frequency
We had these problems with the Joy stick on excavators it was not uncommon that installing dampers rubbers moved the problem to another rpm

One advantage with lead pellets is that if the end plug inside is movable which can be possible it is easy to do some adding and reducing weight.
Bjorn had some solid weights ..the same in weight in lead pellets as a start and adding se what happens .

As I mentioned large rubber foam grips . Bar end weights ..the shop most likely did a good job with the crank --rather rich fueling
NOTHING case closed No vibrations
I Agree it can look better with other grips but this works for me.
 
Interesting discussion. I'm akinda thinking about how the added mass reduces vibration, and whether as gggGary thinks a flexible mount would help with damping. I'm tending to the opposite view.

Vibration forces shake your handlebar, adding weights damps the vibration. I'm suggesting damping results when the vibration forces try to move a heavier object. If the weight is attached, it is part of the handlebar, but if not attached I'm not sure how it will help. For example, if you put lead shot inside the bar but without it being attached, the vibration forces will still shake the bar just as before. The lead shot will be jiggled around and will eventually grind each other to lead dust. Which leads me to think molten lead poured in and set will be much more effective in damping the vibes? Don't think I've explained that very well . . .

As I write this, just notified about Bosco's post above.
I think the difference is changing the resonant frequency (and it's harmonics) vs damping vibration.
:twocents:You can move resonant frequency(s) around some :bike: but you won't avoid them completely.
 
I think the difference is changing the resonant frequency (and it's harmonics) vs damping vibration.
:twocents:You can move resonant frequency(s) around some :bike: but you won't avoid them completely.

Correct. It is very difficult to prevent or "remove" vibration. As gggGary says, normally all you can do is move the resonance (aka the "natural frequency") of the components to a different frequency range where it isn't as objectionable.

The general equation for natural frequency is: FN = sqrt (stiffness / mass) - where "sqrt" means square root.

Figuring out the mass and the stiffness of a complex system like a motorcycle handlebar and its mounting hardware is not as easy as one might think, but some general principles can be stated:

  • if you can increase the mass of the handlebar, you would generally shift the resonance (aka the "natural" frequency) lower. If you could move the natural frequency low enough that it is below the idle speed of the engine, then for the most part, vibration at normal road speeds would be reduced.
  • alternatively....
  • if you could reduce the mass of the handlebars (which is not likely very practical) - AND / OR - increase their stiffness sufficiently, so that the natural frequency was above the redline, you would, once again, greatly reduce the amplitude of the vibrations of the bars at normal operating speeds.
As with most things in life, there is no free lunch, nor any easy solutions. Making the bar mounts more flexible should reduce the vibrations experienced in the rider's hands, but to make a real difference, you would likely have to reduce the stiffness to the point where handling and safety would be affected.
 
I agree, from experience it's extremely difficult to move around natural resonant frequencies. That's why on turbines, compressors etc we go to huge lengths to ensure we don't have any occurring in normal operating ranges.

On a motorcycle, one with a 360 degree crank we are dealing with something quite differently though. Rather than a specific speed related excitation, the entire motorcycle is shaking. At engine RPM. These days motors are built with balance shafts and the like to cancel out the vibration at source in the engine. But the XS650 takes a very different approach and just about everything has rubber isolators. For me, first step in minimising annoying levels of vibration in the handle bars is to fit new isolators, Yamaha ones. They're still available. And go from there.
 
Yes, the ol' Granturismo grips. They've come on most of the old bikes I've purchased. "Real" ones are Italian (they'll make you go faster, lol) ......

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Granturismo.jpg


I like them and have used them in the past, but now I have a new favorite, the Sunline Grand Touring grips ......

Grand Touring Grips.jpg


MyTTR225MC6.jpg


Unfortunately, Sunline stopped making them a few years back, so I have to watch eBay for them.
 
I kind of like the low frequency vibes of the xs650, I have street trackers so; big wide aluminum flat track bars do the trick even though my engine has solid aluminum motor mounts. I also have Ivan’s primary gears and a KTM cush hub on the back.
Honestly have you ever ridden an old big bore 4 cylinder like the Honda Blackbird or a gs1150, your hands literally fall asleep on the highway.
 
The few stock Standard handlebars I’ve dealt with have what appears to be steel in the ends.
I tried scratching at one to see if it was lead but it didn’t mar.
These bars have an opening between the knurls for what I assume is hiding wiring. If that be the case then the metal inserts must be limited in their depth to allow control wiring to enter the hollow of the bars. I’d venture the weights are grip length at most.

If I had to weigh some ends down I’d look into lead anchors.
 
I agree, from experience it's extremely difficult to move around natural resonant frequencies. That's why on turbines, compressors etc we go to huge lengths to ensure we don't have any occurring in normal operating ranges.

On a motorcycle, one with a 360 degree crank we are dealing with something quite differently though. Rather than a specific speed related excitation, the entire motorcycle is shaking. At engine RPM. These days motors are built with balance shafts and the like to cancel out the vibration at source in the engine. But the XS650 takes a very different approach and just about everything has rubber isolators. For me, first step in minimising annoying levels of vibration in the handle bars is to fit new isolators, Yamaha ones. They're still available. And go from there.
I did replace the handlebar rubber mounts with OEM bits a couple of years ago and slathered it with silicone lube. Perhaps now t]since the bars are off I should disassemble, clean and relube, this time with red rubber grease.

I picked up a bag of lead shot today. Probably enough to do 10 bikes lol. When my silicone comes in next week I’ll start mixing up a batch to see what it feels like.

Thanks for everyone’s thoughts and @MaxPete for the engineering knowledge. I may be chasing my tail on this but it’s something to do when it’s too cold outside to ride.
 
Yes I made a big mistake - I bought a $hit load too much lead. Oh well, I’ll hopefully find another use for it. lol. In the bottom of a medium coffee cup, a depth of 3/4” fills one side of my bars, without the silicone binder. Oops - slight miscalculation. If anyone around here needs some lead, you know how to contact me. My nephew reloads his own shotgun shells so maybe he’ll be receiving a present soon.

Btw, this stuff is so small and slippery that it has disaster written all over it if it were to spill.

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Melt and pour in the molten lead. Vibration is quick, small, movements, rapidly changing directions.By adding weight, you increase the inertia (Resistance to change in velocity and direction) of the handle bars. The lead must be bonded to the bars, as to become one. Do not mix lead shot with silicon. It will allow the handle bars to vibrate indipendently from the lead shot.
Use thick soft grips. They allow the handle bars to vibrate indipendently from your hand.
 
Melt and pour in the molten lead. Vibration is quick, small, movements, rapidly changing directions.By adding weight, you increase the inertia (Resistance to change in velocity and direction) of the handle bars. The lead must be bonded to the bars, as to become one. Do not mix lead shot with silicon. It will allow the handle bars to vibrate indipendently from the lead shot.
Use thick soft grips. They allow the handle bars to vibrate indipendently from your hand.
I have to agree with what he said.
 
My silicone came in today and I tried a quick experiment. The material is two part, quite runny and sets up in about 2 hours with a full cure in 24. You can see the lead shot imbedded in the material. Even though it’s not fully cured, it is very firm but still has flexibility. I’m pretty confident it will be tight in the bars and won’t allow the lead to move very much, if at all. I’ll try one side tomoorrow and see how it turns out. I haven’t yet decided whether I’ll premix the lead shot with the silicone or pour the silicone in first and add the lead after. I might have to make the decision on the fly tomorrow.
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