Come to find out, if you do a search on ebay for yamaha handlebar clamp, there are quite a few to choose from and different size bushings for them as well. The RD350, YZ490, XS650, IT490, XS400, XS750, DT250, and TT600 are a few to name that have the rubber bushings/damper for the handlebar clamp. Some with different size bushings so you can fab your mount to that. Cross checked it with Bike Bandit and the bushings are anywhere from $9-$11/EA and some require 2 bushings per side. A little expensive but sure beats having to get a mount with a taper in it. Buy a 1 piece top to the clamp and you're all set! Oh...some require only 1 bushing per side too...I believe the TT600 has one bushing...I'd prefer the 2 bushings tho because they are a little bigger on the tops to sit right into the mount