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 φ8.5
- Exhaust Seal Ring
- Dust Cap Set 12-30 (φ3, φ16, φ18)
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.
