Key Features:
• NEW Larger cylinder head for better cooling and performance
• NEW Steel lined backplate to minimize drag resulting in better performance and increased horsepower
• NEW Piston and Sleeve design increasing both performance and efficiency
• Proven Regulated fuel system for positive fuel flow during all types of flight conditions

Specs:
• Displacement: 14.89cc
• Bore: 27mm
• Stroke: 26mm
• Weight: 553g
• Practical RPM: 2000-17,000

IMPORTANT
The new YS91SR-3DS has a steel lining on the back plate to minimize drag to increase performance and horsepower. Back plate mounting RPM sensors will not work, because the steel lining will block the pick-up. A magnet mounted on the clutch bell or fan unit is recommended. Another option is to replace the steel lined back plate with an all aluminum back plate (YS5865, same as YS91SR), if you choose to use your back plate mounted RPM sensor.