Athena 295cc 72mm Yamaha YZ250 YZ250X WR250 Phathead cylinder head kit 1999-2026 Color:Black 0cc 100+ octane

0cc 100+ octane

Kit includes required engine mounts

Stock (91+ octane)

0cc (95+ octane)Y03 - 5

0cc (95+ octane)

Athena 295cc 72mm Yamaha YZ250 YZ250X WR250 Phathead cylinder head kit 1999-2026 Color:Black 0cc 100+ octaneAthena 295cc 72mm YZ250 YZ250X WR250 Phathead cylinder head kit 1999 2026 Chamber selection: AY22 22cc Same as Athena OE AY21 21cc (95+ octane) AY20 20cc (105+ octane) Phathead Kits include a head shell with one combustion chamber, two sets of o rings, cylinder head nuts, copper washers, some stickers for your bike and tool box and installation instructions.. Phathead cylinder heads are made of 6061 T6 billet aluminum. The material is stronger and