Kawasaki W series

Infobox Motorcycle
left
name=Kawasaki W series


aka=W1, W1SS, W2SS, W2TT, Commander, W3
manufacturer=Kawasaki
production=1967–1975
class=
related=
wheelbase=1415mm (W1)
length=2125mm (W1)
width=880mm (W1)
height=1060mm (W1)
seat height=
engine=624cc
bore x stroke=74.0mm x 72.6mm
power=50 bhp @ 6,500 rpm (W1), 53 bhp @7,000 rpm (W2 & W3)
torque=5.5 Kg/m @5,500 rpm
fuel_capacity=15 litres
fuel_economy=57 mpg
transmission=chain
Wheels= 18", 3.25" rim (front) & 4.00" rim (rear)

History

In 1960 the Akashi-based Kawasaki Aircraft Company acquired an interest in the Meguro motorcycle company, which had obtained a license to produce a copy of the BSA 500 cc A7. Meguro had been Japan's largest motorcycle manufacturer but in the late 1950's 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.

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 650 cc 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 W2's 360-degree 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

In 1999 Kawasaki launched its 676 cc W650 retro-styled motorcycle. This has an overhead camshaft, unit construction engine. The W650 is unconnected with the W1, W2 or W3 other than by being a parallel twin with a 360° crankshaft and a model code that begins with W.

External links

* [http://www.khi.co.jp/mcycle/museum/w1/index_e.html Kawasaki official history of the W1, W2 and W3]