What size shot for bars?

[bradjs]

I'm ready to try the old idea of putting lead shot in the handlebars to quell the vibes. Anyone try this before? I've got Mana bars on my 1200 Sport. The interior hole is about 5/16". I know nothing about guns/ammo. Went to the local shop and they had boxes of lead shot labled #8, #7.5, and #6. Which size would work best?
The vibes on my bike aren't really bad, but my throttle hand/fingers go numb after 40 miles or so. This happens with every bike I've owned, but I thought I'd try something simple like this just to see if it helps.

 

[PP-1753]

Now - this will be a can of worms!

There are many things that will cause vibration of the handlebars - mostly from the engine, but transmission, front and rear suspension, tyres and road surface. But you will need to go into the lever vs fulcrum to fully understand what is happening here.

With the Mana bars, the resonant length is shorter than the stock Sport bars, and also a little higher positioned. By resonant length I mean the distance between the outside of the bar clamps to the end of the bars themselves. If the bar is not positioned centrally, this will contribute; if the location of the levers and mountings is different, this will contribute; the location of the mirrors will contribute; your grip on the throttle will also contribute.

All of these things either damp the vibrations or accentuate them. Simple things like moving the lever mounts in or out will change the resonant frequency (vibration you are experiencing) and/or the amplitude (the strength of the vibration).

A simple test is to get some lead sheet or strip and wrap it around the outside of your handgrips, or they could be put around your mirror stem. Go for a ride and see if there is a difference. If there is, you are heading down the right path. A more permanent solution can be had by changing the bar end weights (I believe these come in three different weights) to something heavier (will provide better damping). I made up a set myself on a lathe, and made the throttle side a few grammes heavier for the same reason you have found. I still have the original bars, but I put 20mm spacers under them to raise them up a bit.

When I first did this there was about 100 cop cars in the R/H mirror - putting the heavier bar end weights on allowed the cop cars to be reduced to around three!

Go play...

 

[bradjs]

Thanks for the reply, but all I asked was what size lead shot to put in the bars. It seems like an easy and harmless way to start. Anybody?

 

[john zibell]

Thanks for the reply, but all I asked was what size lead shot to put in the bars. It seems like an easy and harmless way to start. Anybody?

The problem with just adding weight is you mask the symptom without finding the cause. If you locate the cause, you may not need additional weight to dampen vibration.

That said, the higher the number of the shot, the smaller the pellet. I wouldn't want to handle any shot smaller that 6. I'd even go for 4 shot so If I spill, I don't have so many to chase. If you don't want to play with pellets, get a bar snake. http://www.barsnake.com/about/index.html

 

[bradjs]

I'm not concerned with the cause. I'm sure the vibes are normal for this bike. I've always had issues with my throttle fingers going numb, no matter the bike. On some bikes, just putting on softer or thicker grips helped. Rather than spend the $ for a bar snake, I thought I'd try the lead shot idea. It's cheap, easy, and if it doesn't work, it's no big deal. I can live with the vibes as is, just wanted to give this a "shot".