OS Max-R21 V2

The OS Engines OS Max-R21 V2 (MAX-R21 VER.2) is developed specifically for 1/8 on-road racing and delivers excellent cost performance for entry-level through to sports users. Building on the proven R21 platform, this updated version features a revised crankshaft and carburettor to enhance ease of use, helping drivers achieve consistent performance on track with straightforward tuning and handling.

A blue outer head with a new laser design gives the engine a distinctive Max series look while aiding heat management. With a practical operating range of 4,000–44,000 r.p.m. and an output of 2.75 ps (2.71 hp) at 32,000 r.p.m., the Max-R21 V2 offers a versatile performance envelope suitable for a wide variety of on-road layouts. As part number SCH-OS1F400, this unit maintains the build quality and reliability expected from OS Engines.

Key Features

• Developed for 1/8 on-road racing
• Revised crankshaft and carburettor for improved ease of use
• Blue outer head with new laser design
• Practical RPM range: 4,000–44,000 r.p.m.
• Output: 2.75 ps / 2.71 hp at 32,000 r.p.m.
• Engine weight: 350 g

What’s Included

• RP7 plug
• Exhaust seal ring
• Dust cap set: 3 mm / 16 mm / 18 mm
• Flywheel collet
• Reducer 8.5 mm (purple)

Specifications

• Displacement: 3.49 cc / 0.213 cu.in.
• Bore: 16.08 mm / 0.633 in
• Stroke: 17.20 mm / 0.677 in
• Output: 2.75 ps / 2.71 hp / 32,000 r.p.m.
• Practical RPM range: 4,000–44,000 r.p.m.
• Engine weight: 350 g / 12.35 oz