hmm...as to your smelling of more gas, I don't have a clue. I rarely smell gas on mine, sometimes I get a whiff when I'm really tucked in, but even so, it's momentary. Shimming will definitely improve your bike's performance (low and mid range), I have yet to run across a shim that yielded poor performance gains. I'd advice you to shim, but before you do, read up on it (
http://www.ninjette.org/forums/showthread.php?t=11963) and get the appropriate tools.
As to the jittery RPM needle...was the engine fully warmed up during this time? If it was, then you can always try adjusting it (there's a knob on the left side of the bike). Hope I helped
