Kawasaki A7 Avenger

Kawasaki A7 Avenger

Manufacturer	Kawasaki Motorcycle Corporation
Parent company	Kawasaki Heavy Industries
Production	1967-1971
Successor	Kawasaki S2 Mach II
Class	Standard
Engine	Air-cooled parallel 2-cylinder, Two-stroke, 2 rotary inlet valves
Top speed	160 km/h (99 mph) to 170 km/h (105 mph)
Power	42 hp (30.7 kilowatts)) @ 8000 RPM
Transmission	Chain driven 5-speed
Suspension	Inner spring telescopic front fork, shock absorber and swing arm (rear).
Weight	N/A (dry) 158 kg (350 lb). (wet)
Fuel capacity	13.51 liters (3.57 gallons)
Related	Kawasaki A1 Samurai 250

The A7 Avenger was a 350 cc (21 cu in) Kawasaki motorcycle. It was a standard or Universal Japanese motorcycle sold in the U.S. and abroad from 1967 through 1971.

Development

Kawasaki was the last of the big four Japanese manufacturers to start making motorcycles. In 1960 it bought a share in the Meguro motorcycle company that since the 1930's had made 4-stroke singles up to 500 cc and later twins up to 650 cc for the Japanese and south-east Asian markets. From 1963 Kawasaki took complete control of Meguro, and the Meguro model K 500 cc four-stroke parallel twin was re-badged as a Kawasaki.

The Kawasaki W1 625 cc four-stroke twin was developed from the Meguro K series, which Meguro had developed from a BSA A7 under license. It did not sell as well as hoped because some of its competitors were faster, lighter and had better steering.

Kawasaki developed the lighter Kawasaki A1 Samurai in 1966. It was quickly followed by the larger bore model, the A7 Avenger which is nearly a twin of the Samurai sharing all of the Samurai components aside from pistons, piston rings, different mufflers with reverse cones, it also featured a race developed oiling system called "Injectolube". Oil was not only injected in with the petrol as on the 250 but oil was also fed to the main bearings. The crankcases and crank were also redesigned for use with the "Injectolube" system.

A7SS

The A7SS Avenger has a crossover dual exhaust mounted on the left side and just below the seat. Other than exhaust system, there were no other changes between the standard A7 and A7SS.

An unique engine

The engine was very advanced for its time, only to be seen on race bikes: 2-cylinder, two-stroke, air-cooled, oil injected, dual rotary valve. While other manufactures had utilised the advantages of rotary disc valve induction on small single-cylinder machines, only Kawasaki and Bridgestone produced twin-cylinder machines. Rotary disc valve induction ensures that the all the fuel charge is used and not partly lost (as in a piston ported engine). As a result it produces more power, more torque at low revs and better response throughout the rev range. The engine's ignition air supply began in an air filter canister below the seat and was drawn through a large plenum chamber just above the transmission (gearbox) and behind the cylinder head, then down into the internal passages leading to the carburetor housing feeding the carburetors.

The A7 Avenger had two Mikuni carburetors located on the engine's left and right sides and in line with the crankshaft. The carburetors were enclosed and protected from the elements by carburetor covers fixed to the crankcase. Inboard of each carburetor, and supporting each carburetor, was the disc cover. The rotary disc valve was housed inboard of that cover. In 1969 the ignition system was equipped with a capacitor discharge ignition including thyristor-based switching system then increased the voltage to between 25,000 and 30,000 volts reducing the unburned fuel mixture within the cylinders.

This combination of displacement (338 cc), CDI system, and rotary discs produced 42 hp (30.7 KW) @ 8000 RPM gave the Avenger a power-to-weight ratio of 1 horsepower per 8.5 pounds of weight, a 0-60 mph of 5.2 seconds. At the time the A7 had the most powerful engine per cc of any road bike. Until the 500 triple arrived the A7 was the most powerful bike up to 500 cc, add to this its low weight, only 10 lbs more than the 250, explains why the A7 was so fast.

Almost a 500

During the development of the Kawasaki H1 Mach III, engineers considered using the Avenger's twin-cylinder engine bored out to create the new 500 cc two-stroke power plant as called for in the N100 Plan.

Appearance

• 1968: The A7 was available with either a candy red or candy blue with chrome parts and black frame. The fuel tank was colored with chrome side panels which held rubber knee grips and Kawasaki flag emblem. Front fenders was stainless steel, rear fender was chromed, upper rear shock fork assembly, chain guard, and parts of the fork assembly were chrome plated. Upper fork, headlight and speedometer combination as well as upper rear shock and side-mounted oil reservoir covers were painted. Mufflers were seamless.

• 1969: The A7 and A7SS integrated headlight speedometer unit were separated into two independent units. The colors remained but the fuel tank was completely painted with the tank sides white and "KAWASAKI" stretching along the tank. The SS versions had cross braced handle bars and skid plate.

• 1970: Designation becomes A7A and A7ASS. The Samurai's color scheme was a pearl candy red and white. The fuel tank was red with white sides enhancing the more rectangular style shared by the Kawasaki H1 Mach III. Side covers were white.

• 1971: Designation becomes A7B and A7BSS. All Kawasaki bikes had the angular fuel tanks and fading color decal replacing the white side tank coloring. This model was available in a pastel yellow or pastel white finish and fading gold/yellow decal.

Competitors

1969-1970 contemporaries and competitors of the A7 Avenger were:

• Honda Dream CB350: 36 hp. 0-60 in 6 seconds.
• Suzuki T350 Rebel. 39 hp. 0-60 mph N/A.
• Yamaha (unknown)

Sources: Motoprofi.com

Racing

A7 Avengers have and can participate in the American Historic Racing Motorcycle Association (AHRMA) comoetition. Kawasaki Mach III's successfully raced with Ginger Molloy aboard his "Green Meanie" finishing 2nd just behind Giacomo Agostini's MV Agusta in the 1970 500 cc World Championship. Kawasaki's

See also

• Kawasaki A7R