Need help with this. This thing ran at full bars since it came off showroom floor. Dealer couldn't figure it out they replaced everything. I did notice at the dealer some machines start at 1 bar before you even start it(that's what mine does). And some start at no bars. It's odd that they are not all the same since they're the same machines. I don't get it. I've had the ecu tuned and put a free flowing exhaust on it in hopes that it'll help. I believe it did a bit because it doesn't climb up as fast but it still goes all the way.

[2015 Z Force 800 53/Trail EPS]

If it actually is going to the top of the scale, the engine will have already suffered damage. As it is still running it's unlikely it's an actual reading rather a problem with the temp sensor..which they had thousands of issues with...or a dash/pod problem. Electrical consistency is an unknown with Chinese products so having the gauges all be different is common. This applies to all like fuel, speedometer, RPM and voltage as well. As I recall the temp sensors are a two-part system. One part feeds data to the ECU and the other is for the pod meter alone. And it's not unheard of to have several bad ones in a row so..try replacing it again. Of course it could also have a partly stuck thermostat.

I have the same model and year.  When I first start it temp shows no bars, after warming up it goes to 3 bars then will go to 4 bars for a short time before the fan kicks in and goes back to 3 and sometimes 2.   Since your engine is still running with max bars showing can only be a couple of things.
1. open or shorted wire between the temp sensor.  Most temp sensors reduce resistance as temp rises, this says a short to ground on the temp sensor wire
2. defective temp sensor. Did the dealer replace it?
3. computer analog to digital conversion has a problem.....bad computer.
Thats about it.  I would  have a serious coversation with the service manager and if necessary go to the manager/owner of the business.  You need to know if you are having heating problems before you lose an engine. We have two CFmoto dealers within 50 miles of me and they bend over backwards to ensure you are a happy cutomer.