The O.S. 21XZ-B Spec III is the evolution of a proven powerhouse that has been a winner at numerous races worldwide. With upgrades that enhance its performance and drivability you'll hear the difference in the engine's roar when warming it up. Once you've experienced the speed and power of the Spec III, you'll be on the fast track to the winner's circle! 

Features: 

• Long stroke engine provides more torque
• Enhanced low-to middle-range torque provides a great advantage on tracks that require lots of power
• The newly developed cylinder liner features 3 scavenger ports and 3 exhaust ports, and works with the crankcase to deliver more power with less fuel consumption
• The drop-in type outer head is now lighter, with a lower CG
• Silicon-potted, DLC-coated crankshaft with pressed-in tungsten weights
• Easy-to-tune 21J carburetor with 6.5 mm restrictor

Specifications: 
Displacement: 0.213 cu in (3.49 cc) 
Bore: 0.641 in (16.27 mm) 
Stroke: 0.661 in (16.80 mm) 
Practical rpm: 4,000-42,000 
Power Output: 2.61 hp/2.65 ps @ 34,000 rpm 
Weight: 12.45 oz (353 g) 
Includes: Turbo P-3 plug 
Requires: glow fuel, tuned pipe and manifold