Hi,
I can get an exact rev amount for you on my next ride. But as I recall the revs at 60mph are down approximately 500 rpm, (*but take into account my bike has a slightly shorter 160/60 18 rear tire that replaced the taller stock 130/90 17. That tire change probably bumped the rpms a tiny bit, and since both changes were done simultaneously, I can't say which did what, exactly).
But overall the bike feels so much better to me, it being just a little more long-legged when out on open roads. Around town in, say, a 45mph zone, I feel myself rolling along in third whereas before I would've kicked it into fourth - there's just much less shifting which lends itself to our mid-displacement, triple, two valvers.
By the way, I used the Digi Hud app on my Droid to get an accurate GPS speed reading to compare with my speedometer; GPS 60mph reads as 64mph on the bike's speedo. 70mph GPS is 75mph on the speedo, but bear in mind my rear tire change, so your mph may vary.
There is of course slightly less acceleration as with any vehicle that uses taller gears, but fair acceleration is still there because of the mid-range biased power band of these K75s. Again, have your K75 tuned well to minimize any losses. I'm about to do the ignition advance to see if it works as well as some have claimed. Who knows, this change alone may equalize any slight loss in acceleration from the gearing change. And for some reason Sunoco premium perks this motor up more than all other fuels, don't ask me why.
But the thing is, I don't delude myself that my K75 is a track day tool (I have a club racer SV650 for that). I'm never gonna win drag races with it, but I will enjoy it for what it was made for and I really think the taller gearing enhances the bike's original intent.
The only way I wouldn't do this change would be if the bike would be so overloaded most of the time (even more than my 225 lbs) such as a barn door fairing K75T with a permanent passenger in constant hilly or high altitude conditions. Then of course one would have to wring it out just to keep up with traffic, and every little bit of acceleration would help in that scenario. However, if I rode two up with luggage but only in flat Kansas, I'd happily get the tall gearing.
Re; vibration, my bike has very little. Virtually none in the pegs or Corbin. Now, before I tuned the injection there was a bit in the grips, but all that remains is a faint minor high frequency buzz in the bars. I have the heated grips which are not only hard to the touch (which transmits this vibration), but the internal bar wiring and end-grip design makes it tricky to weight down with a bar snake or similar. Gloves certainly dampen the buzz, but I'd say we're nitpicking to call a K75 buzzy.
