Engines and Components› Engines, Blocks and Components
Athena
Athena 03-24 Yamaha YZ 250 2T Complete Cylinder Kit Big Bore
SKU: A0EF P400485100042
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 P400485100042 |
Videos
1999-2019 Yamaha YZ250 295cc M-Spec Big Bore Kit
This bike’s POWER is INSANE - YZ250 BIG BORE
Part 3: Installing Athena 290 Big Bore Kit- Yamaha WR/ YZ 25
Part 1: Installing Athena 290 Big Bore Kit- Yamaha WR/ YZ 250
2025 Yamaha YZ250 TWO-STROKE Review
2024 Yamaha YZ250X First Ride - Cycle News
Yamaha YZ250: the best bike ever built? | Bike Review | Whiskey Throttle Media
How to STREET LEGAL a YZ250 2-STROKE Dirt Bike
Why You SHOULD Consider a 250cc TWO-STROKE! | 2024 Yamaha YZ250
Yamaha YZ250 Electric Starter Installation | FISCH MOTO
Can a Yamaha YZ250 be a good trail bike?
Athena 304cc Big Bore POWER! WR250F Gets a MASSIVE Upgrade! 🔥
What Is An Athena Big Bore Kit | YZ125 Build | What Comes In The Box
Tearing Down The YZ250 For Rebuild - Athena Big Bore Kit JUNK?
Yamaha YZ250 (300 big bore kit)
This bike’s POWER is INSANE - YZ250 BIG BORE
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.
View Full Return Policy