O.S. SPEED R21 Euro II

O.S.SPEED R21 EURO II - ON-ROAD PERFORMANCE for EUROPE!

This engine inherits the smooth and easy-to-use feeling of the predecessor, O.S. SPEED R21 EURO Spec. And by reviewing the counterbalance of the crankshaft, low and mid end power delivery has been improved. The smooth RPM drop and idling stability are also improved, and the optimum performance is demonstrated even in the long and harsh race scene. Succeeding the previous model, every part has been improved including the outer head with new design to improve the cooling performance.


The outer head adopts the same design as the R2104, which has both high cooling performance and light weight with original laser marking.


Uses the O-ring embedded inner head used in the R2104. The O-ring uses an oil-resistant one (black).


The cylinder with 7 ports and piston have a new design with cooling holes added to the bottom of the exhaust with the newly designed crankcase.


The crankshaft is a specific just for this engine and uses 3 tungsten counterweights. This has improved the torque feeling at medium and low speeds and idling performance.


Comes with 21M2 (B) carburetor, which is popular with many racers for maximum performance. φ8.5 reducer also comes as standard equipment.

Combo set that comes with exhaust pipe set is also available. It is combination of the TR01 (EFRA2098+MR02) especially suits well for the circuit in Europe with longer straights.

Specs:

• Displacement: 3.49cc
• Bore: 16.08mm
• Stroke: 17.20mm
• Output: 2.76hp @ 35.000RPM
• Practical RPM range: 4.000-45.000
• Weight: 340g

Standard accessories:

• Glow plug RP7
• Exhaust seal ring
• Dust cap set (3, 16 & 18mm)