Resolving Handle Bar vibration with the Rizoma Handle Bar plug.

Handle Bar Vibration has always being a bane with all ER6n owners. ER6n Engine being a Parallel Twin employing a 180 degree crankshaft. This results in an uneven firing interval (180 degrees, 540 degrees) which gives the engine note a distinctive "throbbing" quality does not help.
After doing the ZX10R fork upgrade and replacing the stock handle bar clamp & conical handlebar unit to a Rizoma make does help ease the vibration a tad but without a weighted handlebar cap, a significant amount of wobble can still be felt when riding in the mid RPM range.
Hence I had decided to go for the Rizoma Handle bar cap (MA512G G model for gold colored) rated at 65 grams each. After mounting them on, vibration was not noticeably reduced hence I had to do some alteration to further improve the anti vibration capability of the Bar cap. From past experiences with adding after market handlebars, stock handlebar caps which are great vibration dampers will not be usable. Stock caps are usually much heavier and mounted to the handle bar via an threaded mount at the end of the handlebar using a M8 bolt whereas after market handlebar caps are usually mounted using an expandable rubber bush with a M6 bolt.
The strategy was to increase the weight of the Rizoma cap without compromising its look and integrity. Upon closer inspection of the MA512, I eventually came up with the idea of replacing the original 20mm bolt with a 30mm bolt, this replacement will also give me an option to slip in a few 2mm thick M6 washers to act as weight ballast until the handlebar vibration is no longer felt. I ended up using 4 units of the 2mm thick M6 washers before any vibration was noticeable. Design of the MA512 gives you the capability of this mod as it is hollow to house the mounting bolt before the delrin slider is screwed in to cover this hollow recess. Illustration shows a stack of washers threaded into the 30mm M6 bolt right before i screw it in the rubber bushing.