[5][7][8] Based heavily on a licensed version of the post-war, pre-unit construction, 500cc vertical-twin BSA A7, the bikes were clearly aimed at the market then dominated by the classic British twins of the day.

Meguro had been Japan's largest motorcycle manufacturer but in the late 1950s its models had become less competitive and it was short of money.

All have a 360° crankshaft angle, which provides an even firing interval between the two cylinders but high vibration caused by the two pistons rising and falling together.

[2] For the new Kawasaki big bike, the traditional look of Meguro motorcycles was replaced with a sleeker fuel tank, sportier mudguards (fenders) and other details intended to appeal to export markets, especially North America.

This slightly oversquare (i.e., short-stroke) design favors higher engine speeds, while reducing stresses on the crankshaft.

[17] Likewise, in the design of its twin-loop frame, as well as its overall styling, the W1 motorcycle was clearly influenced by classic British road bikes, including shifting with the right foot and braking with the left.

Due to flat sales in North America the W2TT was discontinued in 1969, the W2SS ended in 1970, and finally in 1971 Kawasaki axed the W1SS.

[6][18] The 650 remained popular in Japan, and although some were exported to Europe in the 70s, subsequent models were produced primarily for the domestic market.

[3][14] Kawasaki retro style motorcycles began with the Zephyr range, available in Japan as a 400 cc model.

[25][26] In 2017, a smaller Kawasaki W175 was introduced in Indonesia for the South East Asian market thus becoming the lightest bike in the series.