First off I am no expert, looks like last year you picked up a 2009 rs, how many miles did it have on it, reason I am asking is if the rear shock is bad, that could cause soreness. Then no seat will help. On my RT I rode for over a year with a blown shock from the get go and did not realize it until I rode to spyderfest 1700 miles and had what they call monkey butt- (
dang even the word sounds gross.) After the Shock was replaced at Cowtown under warranty, life was good.:riding: Don't know if your rear shock is the same, but with no one on the bike and pushing down on the rear of the bike and letting go the rear would bounce a little, and it shouldn't.
My original dealership misdiagnosed the condition and gave me wrong info. Since this was my first and only spyder and also a first year touring model had no info to go over......................
.................Now if that doesn't help I want to share my novice thinking here. I have a custom corbin seat. Corbin seats are known for being very hard. Less bounce in the cush means a happier longer ride. Race car seats don't have lots of padding and those drivers are going to be in the cockpit for a long long time. They don't want to be moving around.
One more thing, do you have a back rest and do you have foot pegs? Not sure on an RS if you would because your riding position is slightly different than mine. But remember before I use to have to grip hard with my thighs to feel secure on the bike. And once I added floorboards and highway pegs along with a back rest, a complete change in ride feel. So much more control. I have tried 3 different types of pegs, and they all did the job of locking/anchoring me in the seat. The above photo is old, I believe seal floorboards are made for the RS if it is auto. While I am typing this, does the passenger have a back rest too? That can help.
Before with the OEM I would go about 250 miles and that was enough, of course that was also partly with the bum shock. The Corbin was able to go 400 miles with bum shock, and with corbin and working rear stock shock 700 miles, butt and back fine, just worn out from ride.
Let us know what solution works for you!
Best,
TicketBait