Brand: Athena
Part Number: S410485303077
Part Type: Power valve / exhaust valve assembly
Application: For Athena big-bore cylinder kits

This valve assembly replaces the exhaust power-valve components used in the Athena cylinder system.

In a two-stroke engine like the YZ85:
The power valve adjusts the exhaust port timing.
At low RPM it restricts the port to improve torque.
At high RPM it opens fully for maximum airflow and power.
When installing an Athena big-bore cylinder, the OEM Yamaha valve system usually cannot be reused, so Athena supplies this matched valve assembly.

Package Dimensions: 7.75 x 8.50 x 1.25
Yamaha
2024 - YZ85
2023 - YZ85
2022 - YZ85
2021 - YZ85
2020 - YZ85
2019 - YZ85

Crazy Stickers!!! 

https://www.ebay.com/itm/287173887071