Even with a carb sync, I still had a noticeable amound of vibration on the handlebars. So I tried a slightly modified version of leadshot fix for the vibration. I mixed #7.5 lead shot with wheel bearing grease instead of just putting the lead shot in. The idea was to fill up the space between the balls and also add some intert material. There's a noticeable decrease in vibration now. Up to 5000 is silky smooth, 5000-6000 is still pretty bad, but not as bad as it used to be (5500-6000 has the worst vibration), 6000 and up is much better than it used to be. So overall a definite improvement.
So here's my mastercard moment:
Lead shot, about 7lb (less than half used), 24 bucks
Bearing grease about 1/6 pound, dollar
New rubber expanders for barend weights (old ones are worn) - 4 bucks.
Spoonfeeding your bike with caviar (yes, leadshot mixed with grease looks exactly like caviar and spoon is the most convenient way to get it into the handlebars) - priceless.
-Vadim
P.S. Lead is cheaper if you don't live in NYC and can buy some shotgun shells to get lead, so the whole thing could cost as little as 5 bucks: 4 for a box of rounds and a dollar's worth of greas.
P.P.S. I used a light hammer and a stick to shove the mix in. Since leadshot is mixed with grease it roll easily, but it also doesn't fall all over the place and I was able to fill up the whole bar by working from both sides.