O.S. SPEED R21 SHIMO EDITION 3

Introducing the all-new O.S. SPEED R21 SHIMO EDITION 3 the latest collaboration engine developed with O.S. Team Driver Takaaki Shimo.

Combo Set (1FG01)

Includes:
TR03 EFRA2196 Exhaust
MR05 Manifold

O.S. Engines proudly presents the all-new O.S. SPEED R21 SHIMO EDITION 3. This latest evolution delivers improved drivability, durability, and tuning flexibility for high-level on-road racing.

By using the supplied exhaust spacer(s) on the crankcase exhaust section, the engine achieves a more linear power delivery from low to top end. The cylinder liner has been updated to a 9-port design with a newly treated piston, significantly improving engine life.

The carburetor now features a dust cover ring to reduce fuel leakage and prevent air entering the fuel line, resulting in a more stable and consistent idle.

Visually, the engine stands out with a deep gold outer head and matching venturi, creating a bold, premium appearance. To maximise performance, this combo set includes the TR03 EFRA2196 exhaust and MR05 manifold.

Specifications

• Displacement: 3.49cc / 0.213 cu.in.
• Bore: 16.08mm / 0.633 in.
• Stroke: 17.20mm / 0.677 in.
• Output: 2.80 ps / 2.76 hp @ 35,000 rpm
• Practical RPM Range: 4,000 45,000 rpm
• Engine Weight: 347g / 12.24 oz

Standard Accessories

• Glow Plug T-RP7
• Reducer 8.5
• Exhaust Seal Ring
• Dust Cap Set 12-30 (3, 16, 18)

Key Features

• Additional piston treatment combined with a newly matched 9-port cylinder liner provides a longer service life compared to previous untreated designs.
• R Connecting Rod derived from the R2106 engine to withstand the harsh demands of competitive on-road racing.
• All-new outer head fin design improves heat management and cooling efficiency.
• Ceramic rear bearing applied for enhanced performance and durability.
• Updated crankcase design allows the use of supplied exhaust spacer(s), enabling drivers to fine-tune engine characteristics to suit track conditions.
• Dust cover ring prevents fuel leakage and air ingress, ensuring a more stable and consistent idle.