YAMAHAGX 400 1977 - 1978

　　The Yamaha GX 400, also known as the XS 400 in other markets, was a middle-class motorcycle introduced by Yamaha in 1977 as the first 400cc four-stroke model, alongside its smaller sister, the GX 250 version.

　　The bike featured a cafe racer style, reminiscent of cafe racers at the time, using a square fuel tank. Later models were updated with a teardrop-shaped fuel tank and an up-handle design.

　　In the aesthetic department, the bike packed a round headlight on the front with instruments mounted on top, a square fuel tank, a one-piece dual seat, a dual exhaust system with a muffler mounted on each side, and wire-spoke wheels.

　　In 1978, when the cast alloy wheels were approved, the manufacturer quickly installed the new wheels on both GX 400 and GX 250, changing their names to GX 400SP/250SP. The tank graphics were also changed, driving up the price.

　　Underneath its fuel tank, the 1977 Yamaha GX 400 had installed a 391cc four-stroke parallel-twin air-cooled engine that delivered an output power of 37 hp with a peak force at 8,800 rpm and 33 Nm (24 lb-ft) torque at 8,000 rpm.

　　A six-speed transmission with a manual wet multi-disc clutch handled the bike's power and sent it to the rear end through a final chain drive.

　　The bike packed a telescopic fork on the front, twin side-mounted shock absorbers on the rear, acting as suspension, and a single brake disc on both front and rear, serving as stopping power.