• New

O.S. MAX-21XZ-B V2 Off-Road


O.S. Engine MAX-21XZ-B v2 Off-Road Race Engine

We are pleased to introduce the MAX-21XZ-B Ver. II for drivers who demand performance close to that of our flagship model, the O.S. SPEED 21XZ-B spec. II but at a more affordable price. Many top drivers around the world choose O.S., relying on the renowned linear acceleration to get the best power at the right time. We developed the MAX-21XZ-B Ver. II based on the O.S. SPEED 21XZ-B Spec. II but adopted a single-needle carburetor for easier adjustment. We use the same piston/liner and connecting rod from the flagship model, the O.S. SPEED version, in the new MAX-21XZ-B Ver. II. The crankshaft has the Tungsten counter weights similar to the O.S. SPEED, but without the ultimate DLC coating, offering superb value for money.


Performance that rivals that of the acclaimed Speed 21XZ-B Spec II

Shares the same piston, liner and con rod as the (now discontinued) Speed version

Lightening holes in the cylinder head reduce overall weight

Other enhancements include a lower CG and improved cooling

A 22B2 single needle carb makes tuning a breeze

Optimized power band

Silicone filled crankshaft with tungsten counter weights

Blue anodized head

Incredible throttle response

7mm carb reducer is included


Displacement: 3.49 cc

Bore: 16.27 mm

Stroke: 16.8 mm

Practical RPM range: 3.000-41.500

Power Output: 2.56 hp @ 34.000 rpm

Weight: 362 g