We're riding a 2017 F3L; same 1330 motor as RTL. We do two-up about 80% of the time, and have 12,000 miles on odometer. Spyder is pretty much stock. When riding back country roads doing sightseeing, averaging probably 55 mph, we routinely go 250 miles (400 km) before filling up, and have probably another 25 miles of fuel left before bone dry. Works out usually to be around 38/39 mpg; occasionally just over 40. Using 93 octane. Doesn't seem to change much whether we are two-up, or if I'm solo. We don't waste time, but don't do burnouts. I do keep revs in moderate range, and often downshift manually, usually well before the SE does on its own. However, if we throw in some Interstate or faster highway riding for part of the distance, the fuel consumption will drop to mid-thirties. Extended 75-80 mph travel will drop it more. If we pull our trailer (a very aerodynamic shape, light @ 200#), the consumption rate can drop to low thirties, especially if we also do higher speeds. My gas gauge has 9 bars that light up; I figure on getting 25 miles per bar fairly safely in average (slightly rolling countryside) ryding conditions. We really concentrate far more on enjoying our day, the scenery and the ryde, and don't get too much concerned about the amount of fuel burned. I monitor it out of curiosity; but whether up or down is not going to interfere with or stop us from climbing on the Spyder. Life is what it is, and costs what it takes.
