Engineering

• NINE-PLATE CLUTCH ASSEMBLY: The CRF250R uses a nine-plate design to improve durability and hookup. That helps eliminate slip at peak horsepower, better torque transmission through the clutch pack and greater durability. Plus, the clutch pull is lighter, and you get improved engagement feel.
• BIG BORE / SHORT STROKE: The CRF250R’s 79.0mm bore and short 50.9mm stroke let our engineers create a high-revving engine with plenty of room for large valves. The engine breathes and revs—the two keys to making power in the motocross world.
• DOHC ENGINE LAYOUT: The CRF250R uses a double-overhead-cam (DOHC) engine layout with a unique finger-follower rocker design. Together with the rest of the engine’s architecture (bore and stroke, intake tract, piston, and more), you get more power and a higher redline.
• DOWNDRAFT INTAKE AND EXHAUST LAYOUT: The DOHC cylinder-head design lets our engineers straighten out the CRF250R’s intake and exhaust tracts. The intake is short and just about arrow straight, and the exhaust flows more efficiently too. The straighter ports also help boost low-speed and midrange torque as well as throttle response.
• SINGLE-PIPE EXHAUST: The CRF250R uses a single-pipe header. It routes close to the center of the bike, and its light overall construction helps improve weight distribution. The single muffler uses a pressed-alloy design that lets us shape the muffler body for better rider ergonomics and lighter weight.
• WIDER WATER-PUMP DRIVE GEARS: Making the water-pump drive gear wide gives it more tooth-engagement area for longer component life.
• ENGINE MODE SELECT BUTTON: This simple handlebar-mounted button lets you dial in engine power delivery character with a push of your thumb. Choose between Standard, Smooth and Aggressive, depending on track conditions or rider preference.
• ENGINE OIL SCAVENGE PUMP: Deep in the engine, there’s a special oil scavenge pump that we’ve designed to be especially small and out of the way. While you may never see it, it helps keep the CRF250R’s overall design compact.
• SPECIAL PRIMARY AND TRANSMISSION RATIOS: To handle more broad midrange power and torque, the CRF250R gets special primary and transmission ratios. The ratios let our engineers use the same shaft centerlines as the previous design, so the transmission itself remains light and compact.
• TWO-LEAD SHIFT DRUM: By changing from three to two lead tracks on the shift drum, we improved the shift feel between second and third gears.