I have my 250 setup to run about 16.5:1 air to fuel ratio at highway speeds. I run dual W-1 carters with a standalone A/F gauge. Idle is around 15:1, full throttle 13:1, on flat ground with wind at my back, it will run 17:1, Fuel mileage varies between 20 and 21 mpg @ 65 mph, 3.08 gear 28" tall tires, no overdrive. A/F ratio's will vary at different fuel stations and weather conditions.
