My first Bike, when I was 16 ! The XS400 featured a four-stroke, air-cooled, overhead-cam engine that is commonly called a parallel twin  While the twin cylinders are indeed parallel, the two pistons are offset 180 degrees of crankshaft rotation -- this arrangement greatly reduces linear vibration at the cost of some axial vibration. The 392 cc (23.9 cu in) engine produced 36 bhp (27 kW) @ 8100 rpm. The XS400 was equipped with a 6-speed transmission, chain drive, tachometer, self-canceling turn signals, both electric and kick starters, adjustable rear shock absorbers, center stand, and an automatic fuel petcock. Early and economy models came with spoked wheels and drum brakes, while later and upgraded models received cast alloy wheels and hydraulic disc brakes. Later models also upgraded the early mechanical points ignition system to a modern solid state electronic system. As is customary, the number in the model name indicates the engine displacement. Aside from displacement, the 250CC, 360CC, and 400CC variants were mostly identical except for some economy-minded XS250s and XS360s which omitted the electric starter and self-canceling turn signals. The upgraded Special and Heritage trim levels included styling changes such as stepped seats, megaphone-style exhaust pipes, and swept-back handlebars. Weight is approximately 182 kg (400 lb) (including oil, gas, etc.), and the fuel capacity is 17 L (4.5 US gal).