Use the highways. Sure, back roads may be more fun for Valkyrie riders. However, motorcycles tend to get better gas mileage on roads where the speedometer stays at a steady pace.
Clean the motorcycle's engine. This improve the Valkyrie's efficiency and helps riders get more mileage for the buck.
Keep the Valkyrie's speed in check. According to Motorcycle Insurance, increasing your speed by 5 mph past a speed limit of 55 could mean using an additional two miles worth of gas for each gallon, even if you don't actually travel those two miles.
Keep the tires at a proper inflation. If tires are low in air, that could hurt gas mileage on your Valkyrie and cause you to spend more money.
Take advantage of aerodynamic accessories such as helmets that do not cause wind resistance. Accessories on the bike also can cause the Valkyrie to work harder, therefore hurting gas mileage.
Improve the fuel you pump into your Valkyrie. The better the fuel, the better the gas mileage your Valkyrie will get.