Kawasaki W series

Kawasaki W series

1967 W1SS
Manufacturer	Kawasaki
Also called	W1, W1SS, W2SS, W2TT, Commander, W3
Production	1967–1975
Engine	624cc
Power	50 bhp @ 6,500 rpm (W1), 53 bhp @7,000 rpm (W2 & W3)
Torque	5.5 Kg/m @5,500 rpm
Transmission	chain
Wheelbase	1415mm (W1)
Dimensions	L: 2125mm (W1) W: 880mm (W1) H: 1060mm (W1)
Fuel capacity	15 litres

The Kawasaki W series is a line of motorcycles made by Kawasaki since 1966 that shares some characteristics of classic British parallel twin standard motorcycles. The first Kawasaki W1 had the largest engine displacement of any model manufactured in Japan at the time. Kawasaki continues to build models of the W brand similar to the W1.

Antecedents: Meguro K series

In 1960 the Akashi-based Kawasaki Heavy Industries|Kawasaki Aircraft Company]] acquired an interest in the Meguro motorcycle company, which had obtained a license to produce a copy of the 500 cc BSA A7. 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. Kawasaki's investment enabled Meguro to launch its A7 copy as the K.

The BSA A7, Meguro K and their respective derivatives have a parallel twin-cylinder pushrod pre-unit construction engine. All have a 360° crank angle, which provides an even firing interval between the two cylinders but high vibration caused by the two pistons rising and falling together.

In 1963 the new Kawasaki Motorcycle Corporation completely took over Meguro, but it maintained the licensing agreement with BSA and continued to build the K. The K suffered engine lubrication problems, so in 1965 a revised model called the K2 entered production with improved crankshaft bearings and a larger oil pump. Since the introduction of the K2, the K has tended to become known retrospectively as the K1.

The K2 has a larger timing cover which distinguishes it from the model K and the BSA A7. Also the K2 chassis has a different rear subframe, fuel tank and side panels. These changes gave the K2 a typically conservative Meguro image, dissimilar to the original BSA A7.

Kawasaki W series

In 1967 the K2 was enlarged to 625 cc to become the Kawasaki W1. The Meguro styling was replaced with a sleeker fuel tank, sportier mudguards (fenders) and other details intended to appeal to export markets, especially North America.

The W series are sometimes described as Japanese copies of the 650cc BSA A10, but this is inaccurate. The A10 has a long-stroke engine of 73 mm bore x 84 mm stroke, whereas the W1 and its successors have a short-stroke engine of 74 mm x 72.6 mm. This "over-square" short-stroke engine will tend to accelerate more quickly and potentially achieve a higher revolutions per minute. It will also have a different "character".

During the W-series' production run an increasing number of multi-cylinder models such as the BSA Rocket 3/Triumph Trident, Honda CB750 and Kawasaki's own Mach III and Z1 offered more rapid and less vibratory performance compared with the W series' 360° crank parallel twin. Nevertheless, Kawasaki revised the model in 1968 to become the W2 Commander (with variants including the W2SS and W2TT) and again in 1972 to become the W3. Kawasaki ended W3 production in 1975.

Kawasaki W650 and W800

Main articles: Kawasaki W650 and Kawasaki W800

From 1999 until 2007 Kawasaki built the W650 retro style motorcycle, which has a 676cc overhead camshaft, unit construction engine. Since 2011 it has built a successor model, the W800, which has an enlarged, 773cc version of the same engine. The W650 and W800 are unconnected with the W1, W2 or W3 other than by being parallel twins with a 360° crankshaft and a model code that begins with W.

External links

• Kawasaki official history of the W1, W2 and W3