Kit cilindru ATHENA P400485100104 Big Bore d72 mm, 293 cc

Race Use Only Product - Not intended for street use - Please check details on the "Race use only" footer's section.

WARNING: the cylinder head and base gaskets contained in the kit are specifically developed for Athena cylinders kits. Whenever the cylinder kit is disassembled, replace the gaskets with the specific Athena spare gasket kit: DO NOT use OE replacement gaskets.

The Yamaha YZ 250 has long been a benchmark in motocross performance, delivering explosive power and unmatched agility. For riders seeking a radical upgrade, Athena introduces the Big Bore Cylinder Kit, engineered to transform your YZ 250 into a race-ready powerhouse.

Engineered Evolution for Extreme Performance

This latest version of the Big Bore kit marks a significant evolution over its predecessor. Every component has been redesigned and optimized to deliver more horsepower, enhanced reliability, and sharper throttle response across the entire RPM range.

Redesigned Cylinder: New Port Timing, More Thrust

The aluminum cylinder has been completely re-engineered with a new port timing layout, designed to improve gas flow and maximize combustion efficiency. Internal geometries are optimized to deliver stronger mid-to-high RPM performance while maintaining smooth low-end power.

Recessed Head Design: Precision and Control

The newly recessed cylinder head is the result of advanced engineering. Improved shape and volume.