| Kawasaki Gpz305 | |
| Manufacturer: | Kawasaki |
| Production: | 1983–1994 |
| Class: | Roadster or sport bike |
| Engine: | 306cc SOHC four stroke parallel twin |
| Bore Stroke: | 61mm52.4mm |
| Compression: | 9.7:1 |
| Top Speed: | 98mph |
| Power: | 35bhp @ 10,000 rpm (claimed) |
| Torque: | 18.8lbft @ 8,500 rpm (claimed) |
| Ignition: | Magneto CDI |
| Transmission: | Wet clutch, 6-speed, belt drive |
| Suspension: | Front: telescopic fork 5.9inches travel Rear: swingarm 5.1inches travel |
| Brakes: | Front: 10.2inches disc Rear: 6.3inches drum |
| Tires: | Front: 90/90-18 Dunlop F8 Rear: 110/90-18 Dunlop K130 |
| Rake Trail: | 26.5°, 3.7inches |
| Wheelbase: | 1355mm |
| Length: | 2130mm |
| Width: | 745mm |
| Height: | 1185mm |
| Seat Height: | 30.8inches |
| Wet Weight: | 354.15lb |
| Fuel Capacity: | 16.5L |
| Oil Capacity: | 1.9usqt |
| Fuel Consumption: | 79mpgus |
| Sp: | UK |
The Kawasaki Gpz305 was a 306cc twin cylinder air-cooled SOHC four-stroke motorcycle, produced in 1983 to 1994 by Kawasaki in Japan. The model evolved from the earlier ER250 model and used an overbored 61mm52.4mm version of the 249 cc engine first produced in 1979. Kawasaki gave this model the "Gpz" nomenclature to add to its expanding air-cooled sports bike range, and was marketed as a sports machine. It originally had chain final drive but in 1983 it had a new Kevlar belt final drive first seen on Kawasaki's American styled cruisers.
It was available with a 250 cc engine as the Kawasaki Scorpion, but came in a different colour scheme.
In Cycle Worlds "Ten Best Bikes of 1983", the Gpz305 won best "Under 460 cc Street" motorcycle, because it was the "best of the lightweight roadsters", combining small bike advantages of low weight and low cost with the fun of a sport bike. In their review, Cycle World praised the bike's quick handling in comparison with heavier, more powerful motorcycles, saying that the while 1100cc750cc displacement bikes have a much greater engine power advantage, they typically have 60inches wheelbases, giving the 55.2inches wheelbase Gpz305 an advantage in the ease that it leans into a turn. They also said that while large engines have the advantage of having a wide power band and do not need frequent shifting during casual riding, the Gpz305's lack of power below 7,000 rpm forces the rider to shift frequently to get the most out of the bike, making it more fun to ride. The review said the Gpz305's air-fuel ratio was excessively lean in order to meet EPA emissions requirements, which meant the bike took 10miles of riding to warm up enough to run smoothly without using the choke, and that the bike benefited greatly from re-jetting the carburetor, without losing fuel economy in the process.