The O.S. Speed R21GT .21 On-Road Nitro Engine was developed for the IFMAR World Championships. Compared to the 21XZ-GT, the R21GT offers improved overall performance. The crankcase is a refined version of the R2101, which has an excellent history of on-road racing. The cylinder / piston uses 5 scavenging ports, and 3 exhaust ports and has cleared IFMAR regulations. The unique crankshaft features a DLC coating, silicone ramped intake and press fit counterweight for increased lifespan and reduced vibration. The cooling head is unique to the R21GT and emphasizes cooling performance. The double adjustment 22E (B) GT carburetor is is designed with an emphasis on performance and smooth power delivery out of the corner, which is critical for GT class racing. The T-2060SC exhaust and MB01-70 (M2003SC) header is recommended for the ideal balance of power output and mileage.
- Cylinder / piston: Scavenging 5 ports + exhaust 3 ports according to IFMAR regulation
- Crankshaft: The crankshaft is designed with DLC coating, silicone ramping and press-fitted counterweight to emphasize performance.
- Carburetor: Equipped with 22E (B) GT double adjustment carb and 7mm reducer.
Stroke volume: 3.49cc / 0.213 cu.in.
Bore: 16.08mm / 0.633in.
Stroke: 17.20mm / 0.677in.
Output: 2.65ps / 2.61hp / 34,000rpm
Practical speed: 4,000-42,000 rpm
Weight: 369g / 13.02oz
This product was added to our catalog on May 7, 2021