The 2009 Yamaha YZ85 has approximately 18 horsepower. This is typical for 85cc 2-stroke motocross bikes, which are designed for youth riders. The YZ85 features a 2-stroke, single-cylinder engine that provides a strong power-to-weight ratio, making it popular among young riders looking to compete at higher levels. Keep in mind that this can vary slightly depending on specific tuning and modifications.
Engine Specifications:
- Engine Type: 2-stroke, single-cylinder, liquid-cooled
- Displacement: 84.7cc
- Bore x Stroke: 47.0 mm x 47.8 mm
- Compression Ratio: 8.4:1
- Carburetor: 28mm Keihin PWK
- Power Output: Approximately 18 horsepower at 11,000 RPM
- Transmission: 6-speed, constant mesh
- Final Drive: Chain
Performance Features:
- The 2-stroke engine provides rapid throttle response, especially at higher RPMs.
- It has a reed valve induction system, which helps enhance power and improve throttle control.
- The high-revving nature of the engine makes the YZ85 a competitive machine in motocross events for younger riders, offering plenty of speed and agility on tracks.
Chassis and Suspension:
- Frame: Lightweight steel frame designed for enhanced handling and durability.
- Front Suspension: 36mm KYB inverted fork with 10.8 inches (275mm) of travel.
- Rear Suspension: KYB monoshock with 11.5 inches (292mm) of travel.
- Brakes:
- Front: 220mm disc
- Rear: 190mm disc
- Seat Height: 34.3 inches (872mm)
- Ground Clearance: 12.4 inches (314mm)
- Dry Weight: 157 lbs (71 kg)
Other Notable Features:
- YZ85 has a fully adjustable suspension for setting up according to rider preference and track conditions.
- Rider-friendly ergonomics with a slim and compact design that allows for better control and comfort for younger or shorter riders.
- The YZ85 also features a digital CDI ignition, which allows for improved spark timing and better overall engine performance.
Maintenance:
- As a 2-stroke engine, the YZ85 requires regular maintenance, such as frequent oil changes (for the premix), piston and ring replacements, and exhaust port cleaning to keep the engine running at its peak.
Competition:
- The YZ85 competes against other 85cc 2-stroke bikes, such as the Honda CR85R, Kawasaki KX85, and Suzuki RM85. These bikes are popular in youth motocross classes, especially in racing events like the AMA Amateur National Motocross Championship.
Overall Appeal:
- The 2009 Yamaha YZ85 offers a great balance between power and handling, making it a fantastic bike for intermediate riders who are looking to advance their skills. It’s capable of handling high-speed racing and aggressive jumps on motocross tracks, while also being nimble enough for tighter, technical sections.