Have had our new 2016 rzr xp4 1000 out a few times on the dunes so far now. took it easy for a while to let belt break in. getting popping @ 55mph (hitting rev limiter I guess ). after an hour or so of running you can get past the 55mph with no popping and hit around 65-68 which im guessing is top speed for these on sand ?? anyone else having same problem hitting rev limiter @ 55mph. thanks did it both times on sand.