Fuel Tank The six-gallon fuel tank (mistakenly called a "Blank Tank" by some 5United members) was standard on /5 motorcycles for all years except 1972. However, many 1972 models have the standard tank. The type of fuel tank on a /5 does not necessarily identify the year the motorcycle was built. Fuel tanks were commonly swapped by dealers.
Notice the rubber pads on the sides of the tank. They are large. Many of the small 4 gallon tanks have a small rubber pad on them, instead of the chrome panel.
Side Reflectors It's probably difficult to see in this photo, but BMW mounted the side reflectors on the side of the turnsignal housings. BMW moved the reflectors to the headlight ears and license plate bracket in 1972.
Engine Badges The engine badges are chrome and not painted. The 1972 models had engine badges with black backgrounds.
Silver Carb Tubes The carburetor air tube is silver and not black. The silver tubes turned gold in color with age. Later on in 1973, BMW supplied black carburettor tubes and replacements from your BMW dealer will be black.
Seat Rail The seat seat bar is made of two pieces in 1970 & 1971. For 1972, BMW introduced a one-piece seat bar which remained for the rest of the production run. Aftermarket backrests were available as well.
Seatstrap There is a strap mounted on the seat for 1970 and 1971. The 1972 and 1973 models do not have straps.
Battery Covers Notice that there is no battery cover. That was a 1972 feature, but if your frame has tabs for it, your bike might have had battery covers. But then maybe not. These were very few "absolutes" with respect to factory supplied adornments on these bikes.