Yamaha XS400
 | |
| Engine | 4-stroke 400cc air-cooled engine |
|---|---|
| Top speed | 175 km/h (109 mph) |
| Power | 36 bhp (27 kW) @ 8500 rpm |
| Transmission | 6-speed |
| Suspension | F: Telescoping fork. R: Dual adjustable shock absorber |
| Brakes | F: Single-piston disc R: Drum |
| Weight | 182 kg (401 lb) (wet) |
| Fuel capacity | 17 L (4.5 US gal) |
The Yamaha XS250, XS360, and XS400 are all nearly identical variations of the same XS400 motorcycle platform made by Yamaha from 1977 to 1982. Some bikes received Special, Special II, and Heritage badges denoting "factory custom" features. [1] [2]
Engine
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.
Features
The XS400 was equipped with a 6-speed transmission, Wet plate, 6 friction disk clutch, 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, Maxim, and Heritage trim levels included styling changes such as stepped seats, megaphone-style exhaust pipes, and swept-back handlebars.
Weight is approximately 182 kg (401 lb) (including oil, gas, etc.), and the fuel capacity is 17 L (4.5 US gal).