O.S. Speed R21 Shimo Edition 3 .21 On-Road Nitro Engine

O.S. part # 1FG01

The O.S. Speed R21 Shimo Edition 3 Combo Set is a premium .21 nitro engine package developed for competitive 1/8-scale on-road racing. Created in collaboration with O.S. Team driver Takaaki Shimo, this engine is designed to deliver smooth, linear power from low RPM through the top end for precise throttle control and consistent race performance.

The R21 Shimo Edition 3 features a 9-port cylinder liner, updated piston treatment for improved engine life, and exhaust-side crankcase spacer technology designed to help create a more progressive powerband. The carburetor also uses a dust cover ring to help reduce fuel leakage and air entry, supporting a more stable idle and consistent tuning behavior.

As a combo set, it gives racers a more complete O.S. Speed package for serious 1/8 on-road competition.

Key features

-Genuine O.S. Speed R21 Shimo Edition 3 Combo Set

-.21 nitro engine for 1/8-scale on-road racing

-Developed with Takaaki Shimo

-Smooth, linear power delivery

-9-port cylinder liner

-Updated piston treatment for improved durability

-Exhaust-side crankcase spacer design

-Carburetor dust cover ring for improved sealing and idle stability

-Race-focused O.S. Speed performance

Specs.

Displacement: 3.49 cc / 0.213 cu. in.

Bore: 16.08 mm / 0.633 in.

Stroke: 17.20 mm / 0.677 in.

Output: 2.80 ps (2.76 hp) @ 35,000 rpm

Practical RPM Range: 4,000 – 45,000 rpm

Engine Weight: 347 g / 12.24 oz.

Cylinder Liner: 9-port

Free ground shipping included.