My 2000 Polaris RMK 700 has ACCS. Should I concern myself with barometric pressure when trying to attain proper jetting, or should I only worry about air temperature?
You should concern yourself with air temperature, as the Polaris ACCS system primarily compensates for changes in elevation. The system detects and reacts to changes in barometric pressure, which is influenced more by elevation and much less by temperature. It varies the pressure in the carb float bowls to vary the fuel delivery in an attempt to keep fuel delivery constant as elevation varies.
If you take a look at any of the jetting charts on ACCS equipped sleds, you find the same jet sizes are suggested for all elevations, but as temperature changes then jet sizes change. Therefore, the system primarily compensates for changes in elevation, not temperature.