The 21XZ-B Spec III is that latest evolution of the popular 21XZ-B racing engine from OS. OS are known worldwide for developing race winning 1/8th Off Road World Championship engines and this latest iteration is a result of constant refinement. Using the latest OS design techniques and technology lots of small improvements have added up to a noticeable step forward in performance. These improvements not only enhance the outright performance but also the drivability and usability in high pressure race situations.

• The Spec III has a long stroke for optimum torque
• Improved low-to middle-range torque for corner exits
• 3 scavenger ports and 3 exhaust port cylinder
• Reduced weigh head for a lower CG
• DLC-coated crankshaft with pressed-in tungsten weights
• 21J carburettor with 6.5 mm restrictor

Note: This engine does not include a tuned pipe or manifold.

Specification

Glow Plug: Turbo P-3 Glowplug (Included)

Weight: 353g (12.45 oz)

Capacity: 0.213 cu.in. (3.49cc)

Bore: 16.27mm (0.641")

Stroke: 16.80mm (0.661")

Power Output: 2.61 hp (2.65 ps) @ 34,000rpm

Practical RPM: 4,000 - 42,000

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