TOP END PISTON & GASKET KIT 77MM YAMAHA WR/YZ 250 08-13, ATHENA P5F0770039007B, SET B
4.4 Trustpilot 99.9% positive on eBay
Free UK delivery 2–4 business days
Spread the cost with 
18+, T&Cs apply
Athena Top End Piston Kit includes a forged 4-stroke piston with a bore diameter of 76.97mm and a top end gasket kit. The pistons are made from a special high-performance aluminum alloy with a high silicon content and are produced using state-of-the-art CNC machines. Some pistons feature a molybdenum disulfide coating on the skirts to reduce friction. The included piston rings are made in Japan with wear-resistant coatings (PVD or chromium nitride) for increased durability. The gasket kits are developed with extensive experience and utilize advanced technology for reliable sealing. Technical features include: Big End Pin Diameter (mm) 16x10x42, Bore Diameter (mm) 76.97, Compression Height (mm) 22.30, Compression Ratio 13.5:1, Displacement (cc) 250, Number Of Segments 3, Piston Pin Type Standard, Piston Type Forged. All Athena products produced in greater displacement and power than those provided by the road code of the user's country are intended exclusively for competitive use. Athena declines all responsibility for any use of the product contrary to national regulations. Guarantee of compliance should not be applicable to products destined for competitive sports use or which are used in high-performance or high-speed applications unless it is a clear case of faultiness.
- SKU
- 56-T1003.B_ATH
- Brand
- Athena
- Availability
- In Stock (1)
- Variant Id
- 309782
FULL DESCRIPTION
Athena Top End Piston and Gasket Kit - Forged 4-Stroke Piston 77mm
This Athena Top End Piston Kit provides a perfect combination of two essential engine components for optimal performance and reliability. It includes a forged 4-stroke piston and a comprehensive top-end gasket kit, engineered to work seamlessly together. Athena develops and tests all piston technologies and materials internally, alongside engineering compatible gaskets, ensuring a perfectly tuned kit for high performance and maximum durability.
Key Features:
- Forged Piston Construction: Made from a special high-performance aluminum alloy with a high silicon content for enhanced reliability, resistance, and performance, comparable to Original Equipment (OE) pistons.
- Advanced Manufacturing: Pistons are produced using state-of-the-art numerical control (CNC) machines.
- Reduced Friction: Some piston skirts feature a molybdenum disulfide coating applied by screen printing to further reduce friction, enhancing performance and durability.
- High-Quality Piston Rings: Included piston rings are manufactured in Japan and feature wear-resistant coatings (PVD or chromium nitride) to increase retention and durability, leading to less friction with the cylinder.
- Reliable Gasket Kit: Athena gasket kits are built upon extensive industry experience and constant technological development, adhering to strict manufacturer parameters.
- Precision Sealing: Utilizes the latest generation lasers for perfect cutting quality in gasket production.
- Material Treatments: Employs surface treatments to compensate for irregularities and material stress-relieving processes to improve sealing in critical areas.
- Smooth Profile: The piston's smooth profile ensures regular flow and perfect flame propagation.
Technical Specifications:
- Big End Pin Diameter (mm): 16x10x42
- Bore Diameter (mm): 76.97
- Compression Height (mm): 22.30
- Compression Ratio: 13.5:1
- Displacement (cc): 250
- Number Of Segments: 3
- Piston Pin Type: Standard
- Piston Type: Forged
QUESTIONS? JUST ASK
Talk to John or Phil. Real people, Monday to Friday, 10:00 to 17:00.
Call or email us with your make, model and year and we will check it for you before you order.
UK delivery is £4.99, or free on orders over £60. Orders ship within 3 working days, then delivery takes 2–4 business days. Delivery details
Yes. You have 14 days from delivery to return it, unused and in its original packaging. Contact us first and we will send you the return instructions. Returns policy
By card, PayPal, Apple Pay or Google Pay, or spread the cost with Klarna. Payment is taken securely by Stripe, and the options for your order are shown at checkout.
More answers in our FAQ.
Trade pricing available
Buying parts for your business? Apply for a 2BrosParts trade account.