My overheat symbol is always on and my tach and speedometer needle is sweeping back and forth..

check fuses and connections https://quads.ddns.net/service-manuals/polaris/

if the plug/s are wet , that is flooding and that is excessive fuel or float level , probably from a problem in the needle and seat area where the fuel supply is not being controlled
remove the needle and seat and clean all dirt and rubbish from the needle ans seat area
could come from rust and dirt in the tank so consider an inline fuel filter before the carby/s

check to see if voltage is coming off the stator while running, AC volatage, from all 3 wires. if thats good you prob need a regulator/rectifier.

could be the computer trying to tell you an error code.

water pump, thermostat, air leaking into system, heat sensor malfunction.
press the helpful button, check link below
ATV Thermostat Replacement and Overheating Issues

Hi Peter.

Most all speedometers are connected to your transmission by a large-gauge cable that connects to the transmission wall and to the back of your instrument cluster. It has a cable inside that is coupled to the final gear ratio (wheel RPM) and spins with it. The spinning at the other end, turns a magnet that will affect how the speedometer needle rises against a spring. (If it's a digital read-out, never mind, it'll all be data cables and an RPM sensor somewhere). Most likely the cable is broken or detached. Less likely but possible, the gauge itself is broken. They don't tend to be high wear, though all bets are off on an ATV. Look for the cable. make sure it's seated snugly on both ends, and consider replacing it if nothing else works.

Good Luck
D

Try adjusting you mixture a little richer, 1/8 turn on the fuel screw. If this doesn't help get to idle, you will need to rebuild the carb. make sure you get a complete kit to include the float and throttle springs as well as jets and gaskets. Write down your initial mixture settings and try them again on your rebuilt carb. Should be fine. Bending float arms for travel length is tricky, be careful as they can easily break off making them useless. The rest of the process is pretty straightforward. Ensure you place the needle jet keeper ring on the correct groove and the throttle moves smoothly against the spring tension on the cable above the needle valve.

Dirt inside the fuel line, pump, or needs a new fuel filter. Always happens when you run out and suck fumes/dirt into it. Worst case, the needle pin or gasket on the carburetor has damage. Make sure you have a good air filter with this heat, and time of year to prevent vaper lock.

Hey Dave,
thought I answered this already,,,??? Classic "brass kit" symptom! >>> You need a "brass kit".. this is the needle jet and the jet needle in the center of the carb. The jet needle is the thin needle that hangs down from the center of the slide... The needle jet is the "hole" that the jet needle slides into...Remove the carb, take the bowl off, remove the main jet, the needle jet holder should be able to be gently tapped out, the needle jet is a short brasspiece,, it comes out through the hole where the slide goes,,, reinstall the NEW needle jet, needle jet holder...(it may have a groove in it for correct location). once its seated, you can reinstall the main jet..NOW >> to install a new jet needle,,, remove the slide from the carb.. remove the spring and seat from the slide that holds the needle jet in place.. NOTE which groove the clip is in on the old needle.... (should be the middle one). re install the new needle, reinstall everything else and your atv WILL run fine for a long time..This is a common problem on ATV's..
you need part #'s
1990 Kawasaki BAYOU 300 4X4 KLF300 C2 Carburetor

http://www.kawasakipartshouse.com/oemparts/p/kawasaki/16009-1503/needle-jet-n36w

http://www.kawasakipartshouse.com/oemparts/p/kawasaki/16017-1270/jet-needle-6