My RZR 1000 Turbo could hit 80 mile an hour before the clutch was replaced after the clutch was replaced it was limited to 65 mile an hour. After hours of trying to figure out what was wrong it looks like the spider is thicker and the plastic washer that goes on the end of the spring bottoms out on the back of the clutch which limits the primary clutch from fully engaging. This keeps the belt about 5/16 to 3/8 of an inch from the edge of the primary clutch which reduces your speed. If you have a GoPro camera you can leave the cover off of the clutch Mount the camera take the razor for a ride and you’ll see that the clutch doesn’t close all the way on the belt at top speed which reduces your ultimate speed I removed the plastic washer and I’m back to 80 mile an hour. I don’t have the original Spider to compare with the new one but I believe that is the problem good luck I hope this helps you if you’ve got the same problem.
Utah RZR Rentals