Join Date: Jun 2010
Location: Skippack, PA, USA
Finding an owners manual could be a challenge - try eBay, try dealers, and try places like Beemerboneyard.com
Your mileage should be around 40 MPG, meaning you should be thinking about getting gas somewhere around 160 miles out.
As to what gears when, for casual, "jus' gettin' down th' road" riding, shifting somewhere around 2500-3000 will do the job. Expect to see mileage drop in short-haul local riding with traffic. If you're doing 50-60 MPH on good roads with no traffic, 40-42 MPG makes more sense.
It sounds as though you're in the low-mid 30 MPG range. That suggests the engine is do for a checkup and tuneup.
Not all who wander are lost. Which still leaves room for more than a few lost wanderers...
Red Flash - '03 K1200RS, lightly farkled