Be aware an ATV takes more gas than most small cars. To keep up with traffic the engine will probably work at around 80% of max power and most engines are thirsty at such RPM. A friend had a Polaris XP850, it took 3 liters/10km!!!
3 liters/10km.... is that possible with that size cylinder volume? how could that much gas be run through the intakes of 850cc in 10km? it would literally drown the engine.