Ok I know I have a Harley and they are vibrators, but My RK has developed a "more than normal" vibration at about 1700-2100. Doesn't matter what gear or even free rev. Whether reving up or engine braking down. Just started about a week ago and it shakes the whole bike when it does.

I have checked all mount bolts and they are tight, front mount looks good also. Any clue where to look?

 

Footboard mounts. it happened to me once. Just a chance!
My $0.02

aka Bob

 

something on the frame touching engine somewere

 

Ok ill look it over again. I don't think a footboard would make the whole bike vibrate?

 

You didn't say what year it is. You may want to get the crank runout checked. The 2007+ seem to be prone to excessive crank runout. I have a 2012 with 5k mi and developed a vibration as you describe. It sucks.

 

The compensator can cause all types of noise and vibes. Could just be a loose bolt on the compensator.

 

Tire starting to cup or wear unevenly, can happen within a particular rpm band. May not be your problem, but take a look anyway.

 

My '08 had a bad vibration but mostly idling at the traffic lights. Turned out to be the front motor mount.