There's a bunch of info on vibration on here. Do a search and see what comes up. If it just started, check you top motor mount, seems like that will come up first when "viberation" in a dog is mentioned. Good Luck.
As far as the number on the motor it's hard to tell. Do you know if it has any head wok done? I've got the same motor with a little head work and I'm putting down 110 hp and 125 lbft. Ftlb whatever.
If the 117's on the 05 models are running around 90 hp. then they are a strong 90 because i've not ran up against anything that puts them in the dirt including other newer dogs, H.D,screaming eagles are no match eather.