Innovative and Upgraded Engine The liquid-cooled, DOHC 4-valve, fuel-injected engine features a forward-positioned straight downdraft intake with symmetrical intake and exhaust ports. A new, higher-compression piston and new intake and exhaust valving delivers outstanding engine character with a focus on top-end power delivery. For 2019, the cylinder is also lighter and angled more upright to improve mass-centralization.
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Exclusive Power Tuner App Breaking new ground in the industry – again – Yamaha introduced the Power Tuner app, which brings the power of the GYTR Power Tuner to your iOS® or Android® device. Using WiFi to connect to the bike’s onboard CAN-bus network, the app allows owners to adjust air/fuel mixture and ignition timing maps to tune engine performance for track conditions, record race log information, and monitor a range of data such as maintenance and system diagnosis, engine run time, and more.
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New Electric Starter System The 2019 YZ250F now features a compact electric starter system to minimize restart delays on track and add convenience everywhere else. Powered by a high-capacity and ultra-lightweight, four-cell lithium-ion battery, the system adds minimal weight.
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Adjustable Engine Maps Two-mode adjustable engine mapping allows the rider to adjust engine character with the push of a button, making it easy to tune the YZ250F for changing track or weather conditions between motos.
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Piston, Rod and Crankshaft Balance A flat-top forged piston features a bridge-box design for additional strength with minimal weight. The piston, rings and DLC-coated piston pin, along with the offset cylinder configuration, all reduce friction loss and contribute to quick response. The engine’s intake ports, cam profiles, high-strength connecting rod and optimized crank and counterbalancer all work together to produce potent high-rpm power with user-friendly delivery and exceptional reliability.
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Advanced Fuel Injection The adjustable fuel injection system uses a new 44mm throttle body, fed by a high-pressure electric fuel pump, injects fuel through a new 12-hole Denso® injector. This ensures optimum fuel atomization and air/fuel calibration for excellent rideability in a wide range of riding conditions. The more compact throttle body is 12 percent lighter than the previous unit, too.
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Wraparound Rear Positioned Exhaust Layout An innovative exhaust pipe design improves mass centralization and power development characteristics. Updated for 2019, this layout moves the rear end of the exhaust pipe farther forward and enables a new muffler, positioned closer to the bike’s center of mass.
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Enhanced Cooling Updated radiators are larger and angled more directly in the incoming air stream, for improved cooling under the most demanding race conditions. Inside the engine, a new impellor and water pump boost endurance and durability under the toughest racing conditions.
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Durable Transmission The transmission gears, dogs and shift mechanisms are designed to smooth gear changes and improve durability under the heavy demands of motocross racing, even with lighter gears and selector drum for 2019. The updated YZ250F also features a larger-diameter clutch to boost reliability even further under high-heat conditions.
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