05-21 Yamaha YZ125 YZ 125 58mm 144cc Athena Big Bore Cylinder Top End Piston Kit
Upgrade your Yamaha YZ125 with Athena's 58mm 144cc big bore top end kit featuring a Nikasil cylinder, coated piston, head, studs and complete gaskets.
2005-2021 Yamaha YZ125 / 2020-2022 YZ125X Athena 58mm 144cc Big Bore Top End Kit
📖 Product Description
Take your Yamaha YZ125 to the next level with the legendary Athena 58mm 144cc Big Bore Top End Kit. Designed for riders looking for a substantial increase in horsepower, torque, and throttle response, this premium kit transforms your 125cc engine into a powerful 144cc machine while maintaining the reliability Athena is known for.
Featuring a precision-machined Nikasil-plated aluminum cylinder, matched coated piston, performance cylinder head, and complete installation hardware, this is one of the most complete and dependable big bore kits available. Whether you're racing motocross, riding trails, or rebuilding your engine, this kit delivers outstanding performance and long service life.
🔥 Key Features & Benefits
- Athena 58mm 144cc Big Bore Cylinder Kit delivers increased horsepower and torque.
- Nikasil-plated aluminum cylinder provides superior durability and heat dissipation.
- Complete top end solution with matched piston, cylinder head, gaskets, and hardware.
- Direct bolt-on upgrade with no case machining required.
- Ideal for motocross, woods, and off-road riding requiring stronger low and mid-range power.
- Manufactured by Athena, one of the world's leading performance engine manufacturers.
- All components are brand new and backed by the manufacturer's warranty.
📦 Product Contents
- 1 × Athena 58mm Nikasil-Plated 144cc Big Bore Cylinder
- 1 × Athena Coated Piston Kit (Piston, Rings, Wrist Pin & Circlips)
- 1 × Athena Complete Top End Gasket Set
- 1 × Athena Performance Cylinder Head
- 1 × Athena Head Stud Kit
✅ Compatibility
Designed as a direct performance upgrade for the following Yamaha two-stroke models:
- Yamaha YZ125 (2005-2021)
- Yamaha YZ125X (2020-2022)
❓ Frequently Asked Questions
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Q: Does this increase the engine to 144cc?
A: Yes. The 58mm Athena cylinder increases displacement from 125cc to approximately 144cc for significantly improved power and torque.
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Q: Is this a complete top end kit?
A: Yes. The kit includes the cylinder, coated piston kit, cylinder head, head stud kit, and complete top end gasket set.
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Q: Does this require machining?
A: No. This kit is engineered as a direct bolt-on performance upgrade for the listed models.
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Q: Are all parts covered by warranty?
A: Yes. All Athena components are brand new and covered by the manufacturer's warranty.
🌟 Why Buy from BPRATV
At BPRATV, our promise is unwavering: The Best Parts. The Best Performance. The Best Price. We specialize in high-performance powersports components trusted by riders and builders who demand reliability and results. Every part is carefully selected for precision, durability, and real-world performance. Trust BPRATV to keep your Yamaha YZ125 or YZ125X running at its best, every single time.
Upgrade your Yamaha YZ125 with Athena's legendary 144cc Big Bore performance--order yours today!
BPRATV - The Best Parts. The Best Performance. The Best Price.
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© BPRATV LLC
Due to the nature of high performance and racing applications, BPRATV LLC components are sold without express warranty or any implied warranty of merchantability or fitness for a specific purpose. BPRATV LLC shall not, under any circumstances, be liable for any specific, incidental or consequential damages, including, but not limited to, damage, or loss of property or equipment, loss of profits or revenue(s), cost of purchased or replacement goods, or claims of customers of the purpose, which may arise and/or shall result from sale, installation or use of these parts. Installation of these parts may void vehicle manufacturers warranty coverage and/or may cause the vehicle to be illegal in some locations.
This product is exempt from the emission standards and related requirements of 40 C.F.R. §1051 as provided by 40 C.F.R. §1051.620, and California law. This product is sold only for use in connection with EPA-certified, purpose-built, nonroad vehicles used solely for closed-course, nonroad competition/racing.
