PISTON KIT 08-13 YFM250R 74.00, WOSSNER 8724DA YAMAHA ATV, 1S4-11631-20-A0
4.1 Trustpilot 99.9% positive on eBay
Free UK delivery 2–4 business days
Spread the cost with 
18+, T&Cs apply
The Wossner 8724DA forged piston kit features a 74.00mm bore and is designed for enhanced strength and heat transfer performance. Manufactured in Germany, this high-compression piston has an elliptical shape to ensure even pressure distribution during thermal expansion, reducing the risk of piston failure. Specifications include a bore of 74.00 mm, actual bore diameter of 73.95 mm, hub stroke of 58.00 mm, clearance of 0.05 mm, compression height of 23.50 mm, dome volume of +2.40 cm³, and a Wossner compression ratio of 12.00:1 compared to the OEM compression ratio of 9.50:1. This kit includes piston, lock, pin, and ring set. Cross-reference OEM part numbers are 1S4-11631-20-A0 and 40078M07400. The part number is 56-W4950.A.WO.
- SKU
- 56-W4950.A.WO
- Brand
- Wossner
- Availability
- In Stock (1)
Fitments (14)
| Make | Model | Year |
|---|---|---|
| YAMAHA | XT 250 | 2013 |
| YAMAHA | XT 250 | 2014 |
| YAMAHA | XT 250 | 2015 |
| YAMAHA | XT 250 | 2016 |
| YAMAHA | XT 250 | 2017 |
| YAMAHA | XT 250 | 2018 |
| YAMAHA | XT 250 | 2019 |
| YAMAHA | XT 250 | 2020 |
| YAMAHA | YFM R RAPTOR 250 | 2008 |
| YAMAHA | YFM R RAPTOR 250 | 2009 |
| YAMAHA | YFM R RAPTOR 250 | 2010 |
| YAMAHA | YFM R RAPTOR 250 | 2011 |
| YAMAHA | YFM R RAPTOR 250 | 2012 |
| YAMAHA | YFM R RAPTOR 250 | 2013 |
- General Product Group
- Engine
- General Product Type
- Pistons & Kits
- General Size
- 74mm
- Variant Id
- 256425
FULL DESCRIPTION
Wossner 74.00mm High-Compression Forged Piston Kit
This Wossner 8724DA forged piston kit features a 74.00mm bore and is engineered for enhanced strength and superior heat transfer performance. Manufactured in Germany, this high-compression piston is designed to optimize engine output and durability.
The elliptical design of the piston ensures even pressure distribution as the engine heats up. This intelligent design reduces localized stress and significantly lowers the risk of piston failure or collapse, providing a more reliable performance.
Key Features:
- Forged High-Compression Design: Delivers increased strength and improved performance.
- Enhanced Heat Transfer: Efficiently transfers heat to cylinder walls for better thermal management.
- Elliptical Shape: Promotes uniform pressure distribution during thermal expansion.
- Reduced Stress: Minimizes localized stress, preventing piston collapse.
- German Manufacturing: Ensures high quality and precision engineering.
Specifications:
- Bore Size: 74.00 mm
- Actual Bore Diameter: 73.95 mm
- Hub Stroke: 58.00 mm
- Piston Clearance: 0.05 mm
- Compression Height: 23.50 mm
- Dome Volume: +2.40 cm³
- Wossner Compression Ratio: 12.00:1
- Original Equipment Manufacturer (OEM) Compression Ratio: 9.50:1
QUESTIONS? JUST ASK
Talk to John or Phil. Real people, Monday to Friday, 10:00 to 17:00.
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
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.