| MODEL | JAWA 350-639 1991 |
| Year | 1991 |
| Engine Type | Twin, two-stroke |
| Displacement / Capacity | 344 cc / 20.99 cu in |
| Bore X Stroke | 58.0 x 65.0 mm / 2.3 x 2.6 in |
| Compression Ratio | — |
| Cooling System | Air |
| Max Power | — |
| Max Torque | 32.0 Nm / 23.6 lb-ft @ 4750 rpm |
| Ignition | — |
| Induction | Carburettor |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | Premix |
| Gear Box | — |
| Clutch | — |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | — |
| Rear Suspension | — |
| Front Brakes | Single disc |
| Rear Brakes | Drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | — |
| Rear Tyre | — |
| FUEL SYSTEM | |
| Fuel Capacity | 17 Litres / 4.49 US gal (2.0 L reserve) |
| Fuel Consumption | 4.0 L/100 km / 58.8 mpg |
| Top Speed | 130 km/h / 80.8 mph |
The 639 is the naked version of the Czech air-cooled two-stroke twin, with twin stainless exhaust pipes and a front disc brake. It was offered in red, black and white.
