| MODEL | YAMAHA YX 600S RADIAN 1986 - 1987 |
| Year | 1986 - 1987 |
| Engine Type | Four-stroke, transverse four cylinder, DOHC, 4 valves per cylinder |
| Displacement / Capacity | 599 cc / 36.5 cu in |
| Bore X Stroke | 58.5 x 55.7 mm |
| Compression Ratio | 10.0:1 |
| Cooling System | Air cooled |
| Max Power | 66 hp / 49.2 kW @ 9500 rpm |
| Max Torque | 51.9 Nm / 38.3 ft-lb @ 7500 rpm |
| Ignition | TCI |
| Induction | 4x Mikuni BS30 carburettors |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 6 speed |
| Clutch | Wet multi-plate |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Double cradle |
| Front Suspension | Telescopic forks, coil spring, oil damper, 140 mm / 5.5 in travel |
| Rear Suspension | Swingarm, dual shocks, coil spring, oil damper, 98 mm / 3.9 in travel |
| Front Brakes | 2x 266 mm discs, 2 piston calipers |
| Rear Brakes | Drum |
| DIMENSION SPECS | |
| Overall Length | 2075 mm / 81.7 in |
| Overall Width | 770 mm / 30.3 in |
| Overall Height | 1095 mm / 43.1 in |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | 186 kg |
| Wet Weight | 197 kg / 434 lbs |
| WHEEL SPECS | |
| Front Tyre | 110/90-16 59H |
| Rear Tyre | 130/90-16 67H |
| FUEL SYSTEM | |
| Fuel Capacity | 12 Litres / 3.2 US gal |
| Fuel Consumption | 44 mpg (average) |
| Top Speed | 125 mph |
The Radian was a 1986 middleweight built from existing Yamaha parts: the FJ600 engine retuned for midrange, in an XJ-based frame, with plain standard-bike styling. Reviewers liked the light, stable handling and the value, but criticised weak rear shock damping and a drum rear brake that locks easily.
