Mine starts getting pretty buzzy/vibratey around 5500 RPM and stays that way up to around 7000 RPM, then gets very smooth again. The peak of "buzziness" seems to be around 6200 RPM. I'm fairly certain that this is because the motor is turning at some kind of resonant frequency of the motor/chasis/bike as a whole, which causes the whole bike to "buzz." I used to usually shift as soon as I started getting into the buzz-zone to maintain a nice smooth ride, but I have recently realized that it is a lot more fun to keep the RPM up ABOVE the buzz-zone. A bit excessive for commuting, but definitely more fun for any spirited riding.Iv had my XJ6N 2 years ( It was originaly LAMS restricted her in Aus, NOT ANY MORE ) iv put an arrow dark line exhaust on it and thats it.
The bike has never had a tune since stock so it's running realy rich (when restricted the throttle would only turn one third). It's my first road bike, but if had yamahas all my life.
The power curve on this bike is super smooth when you wrap the juice on. The sweet spot for me is between 8.5 to 10k. Under normal comuting i shift at around 5k (default mindset) the bike most of the time feals very buzzy, i believe this is just how they are.
I'm upping the gearing to 3.20 (15t 48t) (stock is 16t 46t fir those that don't know) and chucking it on the dyno. The bike has heaps of power but i want it to be a bit more torquey at the low end (wwhhhheeeeellllliiieeesss). I never go on the hight way so fuel consuption wont be a problem, if need be ill cruise a gear higher.
But my point is (give me feedback) most of our bikes are quite buzzy/Vibratey, unless your flogging them