Have been riding weekly for few hours each week in same place. Yesterday had an overheating flashing display and full bars on temp with beeping. Stopped and checked coolant level which was between lines on resivoir. Pulled and swapped fan relay, no change. Then ignition off for a minute then back on. After a few seconds the fan cuts on (engine off) and bars go down and it's OK.
Happened 3 times near the end of our 30 mile ride. Mostly slower trails, no climbing or mud. Just dirt, woods, and grass. Radiator clean. I only have about 270 total miles on the machine. So it's not muddy, beat up, or abused. Always have 2 riders so we generally take it easy. We spend 3+ hours for these 30 miles, stopping to fish or crab.
On third overheat I noticed that while trail cruising (10-20 mph) my thumb stays steady but something changed in how the engine was responding from perfectly smooth to light surging and immediately the temp bars started to rise. Took about 5 minutes until beeping and flashing warning. When it happened the third time I knew it was something related because I noticed it the first 2 times but disregarded it. I would compare it to how a new rider rides and tries to ride very slowly but they aren't used to the thumb throttle so they bump it back and forth so the machine surges up and down in rpms especially with rougher terrain (ruts and bumps) but I am very used to my throttle and wasn't moving it at all when this started.
I've never had it back to the dealer because it's 2 hours away and only problem previously was a starter relay that I replaced myself a while back.
Any ideas? We were done for the day so I don't know if it will keep doing it but it probably will. We have over 100 hours on these same trails at easy speeds with no other issue prior to this.