The all new YS91SR 3DS has been developed to produce more power and have better fuel economy than any previous 91 class engine. Several revisions of this engine were tested, ensuring perfect performance and a sizable improvement over the SR. The new larger cylinder head gives better cooling and performance. The steel lined backplate minimizes drag resulting in better performance and horsepower. The piston and sleeve have been optimized to increase both performance and efficiency, and the regulated fuel system gives proven fuel delivery during all flight conditions.

This engine is already loved by 3D pilots worldwide. This is a great power upgrade for your existing 90 size helicopter, or perfect for your new model. You will like the easy starting, constant tuning and proven reliability that YS offers. Team this engine up with a Hatori SB19FH-2 and you will be all set for action.

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 & Sleeve design increasing both performance and efficiency
• Proven Regulated fuel system for positive fuel flow during all types of flight conditions

Specifications:

• Displacement: 14.89cc

• Bore: 27mm

• Stroke: 26mm

• Weight: 553g

• Practical RPM: 2000-17,000

Note: 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.

Check out this video: