| MODEL | RIEJU RS1 CASTROL 2005 |
| Year | 2005 |
| Engine Type | Single cylinder, two-stroke |
| Displacement / Capacity | 50 cc / 3.05 cu in |
| Bore X Stroke | 39.0 x 40.3 mm / 1.5 x 1.6 in |
| Compression Ratio | 12.0:1 |
| Cooling System | Liquid |
| Max Power | 6.6 kW / 9 hp |
| Max Torque | — |
| Ignition | — |
| Induction | Carburettor, Dell'Orto HSA |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | Automix |
| Gear Box | 6-speed |
| Clutch | — |
| Final Drive | — |
| CHASSIS SPECS | |
| Frame | Double cradle steel tube |
| Front Suspension | — |
| Rear Suspension | — |
| Front Brakes | Single 260 mm disc |
| Rear Brakes | Single 200 mm disc |
| DIMENSION SPECS | |
| Overall Length | 1855 mm / 73.0 in |
| Overall Width | 630 mm / 24.8 in |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | — |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 90/90-16 |
| Rear Tyre | 120/80-16 |
| FUEL SYSTEM | |
| Fuel Capacity | 9.0 Litres / 2.38 US gal |
| Fuel Consumption | — |
| Top Speed | — |
A Castrol-liveried version of the 2005 RS1, the 50 cc liquid-cooled two-stroke sports bike with six-speed gearbox and 16-inch wheels. It was distinguished by its red and white colour scheme rather than any mechanical change.
