A compression test will give an indication of the cylinders and valves total health. If you have tested it before with that PepBoys tester then you can compare readings to see if it has changed.

I use a Moroso leakdown tester. With the leakdown test you can readily tell if the rings are seated or if you have valve problem. Good cylinders will leak less than 3%. A finely machined cylinder with hand filed rings (gaps) and multiangel valve job will leak less than 1% after the rings seat!

 

I would call Harry @trinity, maybe you are running a bit fat and washing the cylinders down.

 

Outside of all the good info you have been given already, I have something a bit more simplistic.
Your clutch!
The Rap clutch is weak to start with, even with HD springs they seems to wear quick. Considering your racing up the big hill a couple dozen times an outing, you know that your clutch is taking a beating. With that in mind, you are going to notice the oil will get darker sooner!

 

I was actually running a little lean (180/185mains needle in 4th clip because) My previous rides were at altitude with the needle in the 3rd clip and my plug looked good. At Glamis I raised the needle and rode it. It was not getting hot and the fan never even came ona. I did have alot of black crud on my 6pack rack from the exhaust which was strange being that I was lean. . Bumped up the jetting the 2nd day (185/190 & 5th clip) ran strong before I jacked up my back. Have not touched the bike until today.

 

I changed the oil in my sp500 at 285 miles and it was still clear. I do not know what polaris uses but imagine their synthetic at 22$ a gallon. I was surprised how clean it looked.

 

airraptor, I thought the same thing so when I had the 180/185's needle in 4th, I went to the 3rd needle clip and my **** dyno showed less power. I also tried 175/180 and that was worse too. So I went up to 185/190 needle in 5th and it was better. I have filters directly to the carb boots with no airbox.

 

prolyl because your butt dyno reads low end torque much better than high end pull.

 

Blueleader....what kind of oil are you guys running? Pick here too solve problem