Kawasaki W series
Encyclopedia
Antecedents: Meguro K series
In 1960 the Akashi-based Kawasaki Aircraft CompanyKawasaki Heavy Industries
is an international corporation based in Japan. It has headquarters in both Chūō-ku, Kobe and Minato, Tokyo.The company is named after its founder Shōzō Kawasaki and has no connection with the city of Kawasaki, Kanagawa....
acquired an interest in the Meguro motorcycle company, which had obtained a license to produce a copy of the 500 cc BSA A7
BSA A7
The BSA A7 was a British motorcycle manufactured by Birmingham Small Arms Company at their factory in Armoury Road, Small Heath, Birmingham in 1946. There were actually two versions of the A7, the original 495cc version and an improved 497cc version launched in 1950...
. 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.
- See also Kawasaki Motorcycle CorporationKawasaki Motorcycle CorporationKawasaki motorycles are manufactured by the Motorcycle & Engine division of Kawasaki Heavy Industries at plants in Japan, USA, Philippines, Indonesia and Thailand. The motorcycles have been produced since 1954.-History:...
The BSA A7, Meguro K and their respective derivatives have a parallel twin
Straight-two
A straight-two engine, is a two-cylinder piston engine that has its cylinders arranged side by side....
-cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
pushrod
Overhead valve
An overhead valve engine, also informally called pushrod engine or I-head engine, is a type of piston engine that places the camshaft within the cylinder block , and uses pushrods or rods to actuate rocker arms above the cylinder...
pre-unit construction
Pre-unit construction
Pre-unit construction, also called separate construction, is a motorcycle engine architecture where the engine and gearbox are separate casings, with their own oil reservoirs, and usually attached to parallel plates that also attach to the frame...
engine
Reciprocating engine
A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...
. All have a 360° crank angle, which provides an even firing interval between the two cylinders but high vibration caused by the two piston
Piston
A piston is a component of reciprocating engines, reciprocating pumps, gas compressors and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from...
s 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
Chassis
A chassis consists of an internal framework that supports a man-made object. It is analogous to an animal's skeleton. An example of a chassis is the underpart of a motor vehicle, consisting of the frame with the wheels and machinery.- Vehicles :In the case of vehicles, the term chassis means the...
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 625cc 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
BSA Golden Flash
The BSA Golden Flash was a Birmingham Small Arms Company motorcycle. The Golden Flash was also available in black and chrome, but it was the all-over gold paint scheme that gave it the name, and made it such a popular escape from post war austerity....
, 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
Revolutions per minute
Revolutions per minute is a measure of the frequency of a rotation. It annotates the number of full rotations completed in one minute around a fixed axis...
. 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
BSA Rocket 3/Triumph Trident
The BSA Rocket Three / Triumph Trident was the first true modern superbike and the last major motorcycle developed by Triumph Engineering at Meriden. It was badge-engineered to be sold under both the Triumph and BSA marques. The Rocket3 / Trident was part of Triumph's plan to extend the model...
, Honda CB750
Honda CB750
The Honda CB750 is a motorcycle built in several model series between 1969 and 2003 and 2007 that is recognized as a milestone for Honda's successful introduction of a transverse, overhead camshaft inline four-cylinder engine that has ever since been the dominant sport bike configuration...
and Kawasaki's own Mach III
Kawasaki triple
The Kawasaki Triples were a range of 250 cc to 750 cc motorcycles Kawasaki exported from 1969 to 1980. The engines were air-cooled, three cylinder, two-stroke with two exhaust pipes exiting on the right side of the bike, and one on the left....
and Z1
Kawasaki Z1
The Z1 Kawasaki was a motorcycle introduced in 1972 by Kawasaki Heavy Industries. It has sometimes been described as the world's first superbike. The Z1, along with Honda's CB750 from 1969, introduced the four-cylinder, across the frame, disc-braked layout to a wider public...
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 / W800
From 1999 until 2007 Kawasaki built the W650Kawasaki W650
The W650 is a retro standard motorcycle made by Kawasaki since 1999. It is designed to reflect the appearance and sound of 1960s British parallel twin motorcycles such as the Triumph Bonneville...
retro
Retro
Retro is a culturally outdated or aged style, trend, mode, or fashion, from the overall postmodern past, that has since that time become functionally or superficially the norm once again. The use of "retro" style iconography and imagery interjected into post-modern art, advertising, mass media, etc...
-styled motorcycle. This has a 676cc overhead camshaft
Overhead camshaft
Overhead cam valvetrain configurations place the engine camshaft within the cylinder heads, above the combustion chambers, and drive the valves or lifters in a more direct manner compared to overhead valves and pushrods...
, unit construction
Unit construction
Unit construction is a term used to describe the design of larger motorcycles where the engine and gearbox components share a single casing. The term is sometimes applied to the design of automobile engines and was often loosely applied to motorcycles with rather different internal layouts such as...
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.