Features :
- O.S. .21XZ-R Speed On-Road 13880
- Tungsten-weighted silicone filled crankshaft creates optimum balance for consistent low and mid speed torque, DLC (Diamond-Like Carbon) coating for reduced friction and enhanced performance
- ABC piston and liner construction "A"luminum piston fitted to a
- "B"rass cylinder liner that is "C"hrome plated
- Liner has seven scavenger ports and three exhaust ports for more efficient combustion
- 21M slide valve carburetor with 9mm carb reducer that restricts the airflow helping to increase the amount of torque produced

Specifications : - Displacement: 0.213 cu in (3.49 cc)
- Bore: 0.640" (16.27 mm)
- Stroke: 0.661" (16.8mm)
- Practical RPM: 4,000-45,000
- Power Output: 2.8 hp @ 33,000 RPM
- Weight: 12.1oz (343g)
- Distance Between Mounting Holes Same Side: 0.83" (21mm)
- Distance Between Mounting Holes Opposite Side: 1.45" (37mm)
- Height Bottom of Mounting Tabs/Top of Cylinder Head: 3.10" (78.8mm)
- Width of Mounting Tabs: 1.8" (45mm)
- Distance from Backplate to Front Bearing: 2.6" (65.6mm)
- Distance from Center of Crankshaft to Front Bearing: 1.7" (44mm)
- Distance from end of Crankshaft to Backplate: 3.7" (95.1mm)
- Carburetor Settings,
- Needle Valve: Approximately 3 turns open from fully closed
- Throttle: Approximately 0.5mm open from factory setting with reducer removed
- Metering Needle: Rotate until slotted head is 0.5mm away from ball link body
- Mixture Control Valve: Rotate until slotted head is flush with carb body

Contents :
- O.S. 21XZ-R ABC On-Road Engine w/21M Carburetor, Exhaust
- Gasket RP7 Turbo Glow Plug, 9mm Carb Reducer, Flywheel Collet,
- Instruction Manual, 0.2mm Head Gasket and two Dust Caps