The Kawasaki Z650 (known as KZ650 in North America) was produced as a

standard Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object th ...

motorcycle A motorcycle (motorbike, bike, or trike (if three-wheeled)) is a two or three-wheeled motor vehicle steered by a handlebar. Motorcycle design varies greatly to suit a range of different purposes: long-distance travel, commuting, cruising ...

by Kawasaki from 1976 until 1983. It had a four-cylinder

four-stroke A four-stroke (also four-cycle) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either directio ...

DOHC An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion c ...

air-cooled Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. In all combustion engines, a great percentage of the heat ge ...

wet sump Within piston engines, a wet sump is part of a lubrication system whereby the crankcase sump is used as an integral oil reservoir. An alternative system is the dry sump, whereby oil is pumped from a shallow sump into an external reservoir.Wet sum ...

engine positioned across the frame with two valves per cylinder and a five-speed gearbox. Designed as a middleweight version of the

Kawasaki Z900 The Kawasaki Z900 is a standard motorcycle of the Kawasaki Z series The Kawasaki Z series is a family of standard/ naked bikes manufactured by Kawasaki since 1972. Single cylinder * Z200/KZ200 (1977-1984) * Z125 (2018–present) * Z125 P ...

, the similar-styling had "an attenuated version of the traditional Kawasaki tail fairing". It competed in the market against the smaller

SOHC An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...

Honda CB650 The Honda CB650 is a standard motorcycle produced from 1979 to 1985. It featured a four-cylinder, SOHC, air-cooled, wet sump engine, with two valves per cylinder. The CB650 was a development of the CB550, itself derived from the even earlier ...

. The Z650 was the epitome of the "

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" (UJM). It press-debuted in late 1976 when six US-specification machines were air-shipped from the Akashi works to the UK distributor near London, prior to the London Motorcycle Show. The bikes were assembled and road-shipped to

Edinburgh Edinburgh ( ; gd, Dùn Èideann ) is the capital city of Scotland and one of its 32 Council areas of Scotland, council areas. Historically part of the county of Midlothian (interchangeably Edinburghshire before 1921), it is located in Lothian ...

, Scotland, by Kawasaki UK's road race transporter, to be road-tested by 30 assembled European journalists.UK World Premier of Kawasaki Z650. Kawasaki News, London Motorcycle Show edition 1976. Retrieved 29 December 2021Europe goes Kwackers. "''John Thorpe rides the new Kawasaki Z650 at its world debut in Scotland''". ''New Motorcycle Monthly'', October 1976 No.12, pp.3-5 (

IPC Magazines TI Media (formerly International Publishing Company, IPC Magazines Ltd, IPC Media and Time Inc. UK) was a consumer magazine and digital publisher in the United Kingdom, with a portfolio selling over 350 million copies each year. Most of its tit ...

) Accessed 28 July 2019

Model development

The Z650's project leader was Ben Inamura, who designed the engine. In its seven-year history, the Z650 underwent a number of alterations, as follows:

1977 Z650/KZ650

This first Z650 had a single front 275 mm

disc brake A disc brake is a type of brake that uses the calipers to squeeze pairs of pads against a disc or a "rotor" to create friction. This action slows the rotation of a shaft, such as a vehicle axle, either to reduce its rotational speed or to hol ...

and a 250 mm rear

drum The drum is a member of the percussion group of musical instruments. In the Hornbostel-Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a she ...

. Although the Z650's engine was based on the there were several differences: the 650 used a plain bearing

crankshaft A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion into rotational motion. The crankshaft is a rotating shaft containing one or more crankpins, that are driven by the pistons via the connecting ...

with a HyVo (or "Morse") chain primary drive instead of a gear drive, which necessitated the installation of a third (intermediate) shaft in the transmission to drive the input side of the clutch. Another departure from the Z1 engine design was the use of a shim-under-bucket method of setting valve clearances. (The Z1 engine's shim-over-bucket design caused some mishaps when its camshafts flicked the shims out of position, with consequent damage).

1978 Z650/KZ650

The front brake caliper was resited to the rear of the fork leg and the front

master cylinder In automotive engineering, the master cylinder is a control device that converts force (commonly from a driver's foot) into hydraulic pressure. This device controls slave cylinders located at the other end of the hydraulic brake system. A ...

reservoir shape was changed. A hazard switch was added. Needle roller bearings were fitted to the

swingarm A swingarm, or "swinging arm" (UK), originally known as a swing fork or pivoted fork, is a single or double sided mechanical device which attaches the rear wheel of a motorcycle to its body, allowing it to pivot vertically. The main component of ...

instead of the earlier plain bushings. Tuning modifications were made to the carbs to improve low speed operation. The manual operation fuel tap was replaced with an automatic diaphragm unit. A rear disc brake replaced the earlier drum. Flickr - ronsaunders47 - KAWASAKI Z650

1979 Z650/KZ650

This model had a self-adjusting (rather than manually-adjusted) camchain tensioner. For US-only models, an air injection system for emissions reduction was fitted. This model was the first Kawasaki to use all-weather sintered disc pads and drilled brake discs to improve braking in the wet. A derivative version, the KZ650SR had " chopper styling" with a fat 16-inch rear wheel.

1980 Z650/KZ650

A HyVo-type timing chain replaced of the earlier roller chain.Kawasaki Service Manual Part #99924-1007-03 3rd ed. dtd. September 10, 1981, p. 289 An "LTD" model became available with just a single front disc brake and a rear drum brake.

1981 Z650/KZ650

Electronic ignition (instead of points) was introduced. The front end from the 750E was grafted on meaning a change to the brakes, front wheel and clocks. The kick-starter was removed and a passenger grab rail was fitted. Larger 32mm Mikuni CV carbs were fitted, allowing the redline to be lifted from 9,000 to 9,500 rpm. A new generation of Kawasaki cruisers, the "CSR" was introduced.

1982 Z650/KZ650

Changes included new CV carbs, a clutch upgrade, modified fork internals, new switchgear, tail light, and different rear shocks.

1983 Z650/KZ650

Some minor updates including new pistons with four rings, and changes to the cylinder head and cover. After 1983 the KZ650 is surpassed by the GPZ models.

References

* {{cite web , url=https://www.cyclechaos.com/wiki/Kawasaki_KZ650C , title=Kawasaki KZ650C , website=CycleChaos Standard motorcycles Motorcycles introduced in 1976 Z650