Engines and Components› Pistons and Piston Rings
Athena
Athena 20-24 Yamaha WR 250 F 85mm Bore 300cc Big Bore Cylinder Kit
SKU: A0EF P400485100073
Moderate — 2–4 hours
Description
Fitment
Fitment Guaranteed
Don’t gamble
on fit.
Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.
Available on iOS & Android
Specifications
| Brand | Athena |
| Part Number | A0EF P400485100073 |
Videos
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Athena 4-Stroke Cylinder Kit Review by MotoEverything
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Part 1: Installing Athena 290 Big Bore Kit- Yamaha WR/ YZ 250
Part 6: Installing Athena 290 Big Bore Kit- Yamaha WR/ YZ 25
Buy with Confidence
Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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