21XZ-R O.S. Engine On-Road ABC w/21M  [OSMG2040]

O.S. is gearing up for triumph at major 1/8 scale on-road championships utilizing the 21XZ-R ABC!
Tungsten-weighted crankshaft creates maximum stability for constant low- and mid-speed torque.

The cylinder liner features 7 scavenger ports and 3 exhaust ports for substantially more efficient combustion.

The crankcase and 21M carburetor are newly created.

Lighter piston.

Stronger con pole.

• Stock volume: OSMG2040
• Displacement: 0.284 cu in (4.65 cc)
• Bore: 0.728 in (18.5 mm)
• Stroke: 0.681 in (17.3 mm)
• Practical rpm: 4,000-38,000
• Power manufacturing: 3.31 hp @ 32,000 rpm
• Weight: 13.1 oz (375 g)