2Bros Parts

PISTON KIT B 77MM YAMAHA YZ 250F 14-15, ATHENA S5F07700008B

£166.55

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ATHENA Forged Piston Kit B, 77mm Bore Diameter (76.97 mm). This piston is made from a special high-performance aluminum alloy with high silicon content and is produced using cutting-edge CNC machining tools ensuring dimensional tolerances of less than 0.01 mm. Some piston skirts are treated with a molybdenum disulfide coating applied by screen printing to reduce friction. The piston rings are produced in Japan with wear-resistant coatings to increase retention and durability. This kit contains the piston, pin, circlips, and piston rings. Technical features include: Big End Pin Diameter 16x10x42 mm, Compression Height 20.40 mm, Compression Ratio 13.5:1, Displacement 250 cc, Net Weight 0.20 Kg, Number Of Segments 2, Piston Pin Type Standard, Piston Type Forged.

Specifications
SKU
56-W4961.B.ATH
Brand
Athena
Availability
In Stock (2)

Fitments (29)

MakeModelYear
YAMAHAWR 250F2015
YAMAHAWR 250F2016
YAMAHAWR 250F2017
YAMAHAWR 250F2018
YAMAHAWR 250F2019
YAMAHAWRF 2502014
YAMAHAWRF 2502015
YAMAHAWRF 2502016
YAMAHAWRF 2502017
YAMAHAWRF 2502018
YAMAHAYZ 250F2014
YAMAHAYZ 250F2015
YAMAHAYZ 250F2016
YAMAHAYZ 250F2017
YAMAHAYZ 250F2018
YAMAHAYZ 250FX2014
YAMAHAYZ 250FX2015
YAMAHAYZ 250FX2016
YAMAHAYZ 250FX2017
YAMAHAYZ 250FX2018
YAMAHAYZ 250FX2019
YAMAHAYZF 2502014
YAMAHAYZF 2502015
YAMAHAYZF X 2502014
YAMAHAYZF X 2502015
YAMAHAYZF X 2502016
YAMAHAYZF X 2502017
YAMAHAYZF X 2502018
YAMAHAYZF X 2502019
General Product Group
Engine
General Product Type
Pistons & Kits
General Size
77mm
Variant Id
289767
Delivery2–4 business days
14-Day ReturnsHassle-free
Easy CheckoutCard friendly
Product details

FULL DESCRIPTION

Athena Forged Piston Kit B - 77mm Bore

Enhance the performance and durability of your motorcycle with the Athena Forged Piston Kit B. Crafted from a special high-performance aluminum alloy with a high silicon content, these pistons are designed to meet or exceed Original Equipment (OE) standards, offering greater resistance and excellent performance for off-road applications.

Produced using cutting-edge CNC machining tools, Athena pistons achieve dimensional tolerances of less than 0.01 mm. The perfectly smooth piston profile promotes regular flow and optimal flame propagation. Some piston skirts feature a molybdenum disulfide coating applied via screen printing to further reduce friction, boosting performance and longevity.

Every Athena piston is engineered in Italy and rigorously tested on engine dynamometer benches and on the track to validate performance under extreme conditions. This piston kit includes the piston, pin, circlips, and piston rings. The piston rings are produced in Japan with wear-resistant coatings (PVD or chromium nitride) for increased retention and durability, ensuring they adapt perfectly to the cylinder liner even at low tangential loads.

Key Features:

  • Forged piston for superior strength and performance.
  • High silicon aluminum alloy for enhanced reliability and resistance.
  • Precision CNC machining for tight tolerances (less than 0.01 mm).
  • Smooth profile for improved airflow and flame propagation.
  • Optional molybdenum disulfide coating on some skirts to reduce friction.
  • Includes piston, pin, circlips, and piston rings.
  • High-quality piston rings with wear-resistant coatings.
  • Designed and tested by Athena R&D for extreme conditions.

Technical Specifications:

  • Big End Pin Diameter: 16x10x42 mm
  • Bore Diameter: 76.97 mm
  • Compression Height: 20.40 mm
  • Compression Ratio: 13.5:1
  • Displacement: 250 cc
  • Net Weight: 0.20 kg
  • Number of Segments: 2
  • Piston Pin Type: Standard
  • Piston Type: Forged
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Check the fitment table on this page against your make, model and year. Not sure? Call or email us 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

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