Built around Kawasaki's sport motorcycle platform, the 1985 Kawasaki GPZ 305 Belt Drive utilizes a 306 cc (18.7 cu in) air-cooled twin, four-stroke layout. In factory specification, peak output is rated at 27 HP (19.7 kW) at 10,000 rpm while maximum torque reaches 25.5 Nm (18.8 lb-ft), transferring power to the rear wheel through a 6-speed gearbox and belt final drive. With a specific output of 88.2 HP per liter, the engine character is indicating a tractable, stress-free state of tune focused on everyday usability and broad torque delivery.
On the scales, the GPZ 305 Belt Drive measures 164 kg (362 lbs) wet (curb), translating to a power-to-weight ratio of 0.16 HP/kg (6.07 kg per horsepower). Rider ergonomics and chassis geometry center around a 784 mm (30.9 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,355 mm (53.3 in) wheelbase engineered for quick, flickable steering geometry. The 16.5-liter (4.4 US gal) fuel tank paired with a rated consumption of 3.62 L/100 km provides an estimated theoretical range of roughly 456 km (283 miles) between fill-ups, while factory top speed is listed at 140 km/h (87 mph).
Within MotoLibrary's Kawasaki archive, this model family spans 7 indexed model years from 1984 to 1990, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
88.2 HP/L
Power-to-Weight
0.16 HP/kg (6.07 kg/HP)
Theoretical Range
~456 km (283 mi)
Engine
Displacement306.0 ccm (18.67 cubic inches)
Engine TypeTwin, four-stroke
Engine DetailsTwin, four-stroke
Power27.0 HP (19.7 kW)) @ 10000 RPM
Torque25.5 Nm (2.6 kgf-m or 18.8 ft.lbs)
Compression9.7:1
Bore x Stroke61.0 x 52.4 mm (2.4 x 2.1 inches)
Valves/Cylinder2
Fuel SystemCarburettor. 2 x 32mm Keihin CVi carburetors
Fuel ControlOverhead Cams (OHC)
IgnitionMagneto CDI
LubricationForced feed lubrication
CoolingAir
Transmission
Gearbox6-speed
Final DriveBelt (final drive)
ClutchWet clutch
Performance
Top Speed140.0 km/h (87.0 mph)
Fuel Consumption3.62 litres/100 km (27.6 km/l or 64.98 mpg)
Greenhouse Gases84.0 CO2 g/km. (CO2 - Carbon dioxide emission)
Chassis
Rake26.5°
Trail95 mm (3.7 inches)
Front SuspensionTelescopic forks
Rear SuspensionSwing arm
Wheelbase1355 mm (53.3 inches)
Wheels & Brakes
Front Tyre90/90-18
Rear Tyre110/80-18
Front BrakesDouble disc
Rear BrakesExpanding brake
Dimensions & Weight
Dry Weight147.0 kg (324.1 pounds)
Weight incl.164.0 kg (361.6 pounds)
Power/Weight0.1837 HP/kg
Seat Height784 mm (30.9 inches) If adjustable, lowest setting.
Fuel Capacity16.50 litres (4.36 US gallons)
Other
StarterElectric
Notes
Area code UK,FG: frame range EX305B 004601 - EX305B 006700, engine range KZ305AG 001801 - KZ305AG 003000. Area code UK,FG: frame range EX305B 004601 - EX305B 006700, engine range KZ305AE 027501 - KZ305AE 028400.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Torque
Torque is useful for judging real-world pull, especially for touring, commuting and loaded riding.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
