youre slightly confused . the f650gs and f800gs are parallel twins with the 650 being the more commuter oriented of the two. most comparisons are between the 2 f bikes. the g650gs is the thumper and besides lacking another cylinder is about as capable as the f650gs . the newer g650gs is way different from the old ones more street oriented and heavier. there are more farkles for the f bike than Power train F 650 GS Clutch Multi-plate clutch running in oil bath Primary transmission 37/72 = 1:1.946 Transmission 5-speed, with claw-action shift, integrated into engine block Gear ratios 1st gear = 2.75 in the transmission 2nd gear = 1.75 3rd gear = 1.31 4th gear = 1.05 The F 650 is powered by a BMW-designed, single-cylinder engine embodying technologies not seen on other “thumpers.” For 2006, the engine’s technological resume stretches to include 2 Spark ignition for the four-valve cylinder head and a new and advanced BMS-C II computerized engine-control unit that dynamically manages spark and fuel The BMW F 650 GS model is a Enduro / offroad bike manufactured by BMW . In this version sold from year 2008 , the dry weight is 179.0 kg (394.6 pounds) and it is equipped with a Twin, four-stroke motor. The engine produces a maximum peak output power of 69.73 HP (50.9 kW) @ 7000 RPM and a maximum torque of 75.00 Nm (7.6 kgf-m or 55.3 ft.lbs YCj26.