| MODEL | JAWA 638 1984 - 1994 |
| Year | 1984 - 1994 |
| Engine Type | Two stroke, parallel twin |
| Displacement / Capacity | 343.4 cc / 21.0 cu in |
| Bore X Stroke | 58 x 65 mm |
| Compression Ratio | 9.8:1 |
| Cooling System | Air cooled |
| Max Power | 17.2 kW / 23.5 hp @ 5250 rpm |
| Max Torque | 31.4 Nm / 3.2 kgf-m / 23.2 lb-ft @ 4750 rpm |
| Ignition | Magneto VAPE A67 contactless |
| Induction | Jikov 28-29 CE horizontal slide carburetor |
| Start System | Kick |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 4 Speed |
| Clutch | Multi disc in oil bath |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Tubular, double, closed |
| Front Suspension | Hydraulic telescopic fork, steel coil springs, 150 mm / 5.9 in travel |
| Rear Suspension | Swingarm, hydraulic suspension units, coil springs, 80 mm / 3.1 in travel |
| Front Brakes | 265 mm disc, hydraulic |
| Rear Brakes | 165 mm drum, mechanical |
| DIMENSION SPECS | |
| Overall Length | 2100 mm / 82.7 in |
| Overall Width | 780 mm / 30.7 in |
| Overall Height | 1160 mm / 45.7 in |
| Seat Height | 820 mm / 32.3 in |
| Wheelbase | 1370 mm / 53.9 in |
| Ground Clearance | 120 mm / 4.7 in |
| Dry Weight | 149 kg / 328 lb |
| Wet Weight | 162 kg / 357 lb |
| WHEEL SPECS | |
| Front Tyre | 2.15 B x 18 |
| Rear Tyre | 2.15 B x 18 |
| FUEL SYSTEM | |
| Fuel Capacity | 17 Litres / 4.5 US gal |
| Fuel Consumption | — |
| Top Speed | — |
The 638 was the Jawa 350 twin sport roadster of the mid-1980s to mid-1990s, a development of the 634 with a front disc brake and a closed double-tube frame. It has a kick-started air-cooled two-stroke twin with a four-speed gearbox. Light and narrow, it was a practical everyday machine in Czechoslovakia and export markets.
