My gas gauge was showing empty and the light was on after 49 miles and when I added gas it only took 2.9 gallons for a 4.9 gallon tank. What is the fix for this? Also, 17 mpg seems low. Any suggestions?
Thanks.

MpG is usually low in these machines.. i get around 120km with a full tank but regarding the guge is just a feature that cfmoto doesn't seem to fix. Some users have fiddled around with the floater inside the tank and it made it better but don't know what they did exactly.
I get the same thing, flashing empty and when i fill it up it only takes 6-7 liters which is about half the tank

Mine does the exact same thing and my last UTV (Honda pioneer 500) did it as well. I just set the trip odometer and keep tabs on that instead.

Same for me as well, fuel gauge is blinking and shows almost empty, but when I fill her up she is full after approx 10ltrs of gasoline. So yeah, the gauge is way off on a 18ltr tank...

I have a 600 touring. I weigh 260 lbs and my wife about 170. I have a heavily loaded front box and same on rear plus a flat aux fuel pack (3.8 gal) on the rear. I have kept track of mileage when fueling after each ride. Most of my rides have been 100+ miles and I have consistently gotten a minimum of 25mpg. Mind you, I ride mountain trails in New Mexico and Colorado with steep inclines so the engine is not babied at all. My fuel gauge also is unreliable so I go strictly by trip odometer and Garmin. Hope this helps others. Love my machine!!

Mine wasn't registering at all when it was new. I took it back and they changed the fuel sensor under warranty. Now it works perfectly.