The Yamaha XJ 650 Seca released in 1981 has a four-stroke, transverse four-cylinder, DOHC, 2 valves per cylinder and a capacity of 653cc/39.8 cu-in. The Hitachi carburetor induction, transistorized ignition, and electric start give it a maximum power of 71 hp/51.8 kW @ 9400 rpm and maximum torque of 57 Nm/42 lb-ft @ 7500 rpm. It has a 5-speed transmission, wet multi-plate clutch with 7 steel 8 friction plates, and a shaft final drive with a gear ratio of 1st 2.187 (35/16), 2nd 1.500 (30/20), 3rd 1.153 (30/26), 4th 0.933 (28/30), 5th 0.812 (26/32). The frame is a tubular steel dual cradle frame and has a 36mm Kayaba fork, 142mm/5.5in front wheel travel, and dual Kayaba shocks in the rear with a 93mm/3.6in rear wheel travel. Its front brakes consist of 2x 268mm disc 1 piston calipers while its rear brakes are drums. It has a wheelbase of 1445mm/56.8in, a seat height of 780mm/30.7in, a ground clearance of 145mm/5.7in, and a dry weight of 206kg/465lbs. The fuel capacity is 19.5 liters/5.1 US gal and its average consumption is 48.6 mpg. Its standing 1/4 mile is 12.6 sec/171 km/h.
Technical specifications:
Make Model: Yamaha XJ 650 Seca
| Year | 1981 |
|---|---|
| Engine | Four stroke, transverse four cylinder, DOHC, 2 valves per cylinder, |
| Capacity | 653 cc / 39.8 cu-in |
| Bore x Stroke | 63 52.4 mm |
| Cooling System | Air-cooled |
| Compression Ratio | 9.2:1 |
| Induction | 4x 32mm Hitachi carburetors |
| Ignition | Transistorized |
| Starting | Electric |
| Max Power | 71 hp / 51.8 kW @ 9400 rpm |
| Max Torque | 57 Nm / 42 lb-ft @ 7500 rpm |
| Clutch | Wet Multiplate; 7 Steel 8 Friction |
| Transmission | 5 Speed |
| Final Drive | Shaft |
| Gear Ratio | 1st 2.187 (35/16) 2nd 1.500 (30/20) 3rd 1.153 (30/26) 4th 0.933 (28/30) 5th 0.812 (26/32) |
| Frame | Tubular steel dual cradle frame |
| Front Suspension | 36mm Kayaba forks |
| Front Wheel Travel | 142 mm / 5.5 in |
| Rear Suspension | Duel Kayaba shocks |
| Rear Wheel Travel | 93 mm / 3.6 in |
| Front Brakes | 2x 268mm disc 1 piston calipers |
| Rear Brakes | Drum |
| Front Tyre | 3.25-19 |
| Rear Tyre | 120/90-18 |
| Wheelbase | 1445 mm / 56.8 in |
| Seat Height | 780 mm / 30.7 in |
| Ground Clearance | 145 mm / 5.7 in |
| Dry Weight | 206 kg / 465 lbs |
| Fuel Capacity | 19.5 Litres / 5.1 US gal |
| Consumption Average | 48.6 mpg |
| Standing 1/4 Mile | 12.6 sec. / 171 km/h |
