Wiseco GP Series Piston Kit with Gaskets - Yamaha YZ125 / YZ125X (2005-2022) - 56.00mm Bore (+2.00mm BIG BORE) - 2-Stroke Race-Spec
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Wiseco GP Series Piston Kit with Gaskets - Yamaha YZ125 / YZ125X - BIG BORE
The Wiseco GP Series represents the pinnacle of 2-stroke piston technology for the legendary Yamaha YZ125. This is a BIG BORE kit (+2.00mm) that increases displacement from 125cc to 134cc - giving your YZ125 significant power gains while maintaining the GP Series race-spec features!
š„ BIG BORE: 125cc ā 134cc (+7.2%!)
This +2.00mm big bore kit provides a 9cc displacement increase - that's 7.2% more displacement for noticeably improved power throughout the rev range!
š GP Series Race-Spec Features
- Electra Coating - Crown, ring groove(s), and pin bores coated for maximum wear resistance
- ArmorGlideĀ® Skirt Coating - Protection from micro-welding, galling, and detonation
- Extra Lightening Operations - Enhanced throttle response
- Made in USA - Engineered, forged, and machined in the USA
Kit Includes
- Wiseco GP Series Piston - Premium 4032 aluminum alloy with Electra + ArmorGlideĀ®
- Ring Set
- Wrist Pin
- Circlips
- Wrist Pin Bearing
- Top End Gasket Set
Key Features
- GP Series design for professional-level racing performance
- 4032 aluminum alloy construction - optimized for 2-stroke applications
- Dual coating system - Electra + ArmorGlideĀ® for ultimate protection
- Designed for endurance and sustained RPM riding
- Complete top-end gasket kit included
- Wrist pin bearing included - everything for a complete rebuild
Displacement Increase
- Stock Bore: 54.00mm = 125cc
- Big Bore: 56.00mm = 134cc (+7.2% displacement!)
Important Notes
- Cylinder must be bored to 56.00mm
- Wiseco ring types are not interchangeable
- Wiseco pistons can be fitted only with Wiseco rings
- Cylinder sleeves must be purchased separately if needed
Piston Specifications
- Bore Size: 56.00 mm (+2.00mm Big Bore)
- Piston Diameter: 55.95 mm
- Stroke Length: 54.50 mm
- Material: 4032 Aluminum Alloy
- Skirt Coating: ArmorGlideĀ® + Electra
- Style: GP Series
Engine Specifications
- Displacement: 134cc (up from 125cc)
- Engine Type: 2-Stroke
- Weight: 0.9 lbs
Fitment
Yamaha:
- YZ125: 2005-2021 (17 years!)
- YZ125X: 2020-2022 (enduro variant)
GP Series vs Pro-Lite Big Bore
This is the GP Series 56mm big bore with race-spec Electra + ArmorGlide coatings. We also offer a Pro-Lite 56mm big bore (SKU 0903-1160) without the advanced coatings at a lower price point.
Why Wiseco GP Series Big Bore?
Combine the legendary YZ125 platform with +9cc displacement AND GP Series race technology for the ultimate competitive advantage!
š¦ Shipping Information
In-stock items ship next business day. ModQuad parts dispatch Monday through Thursday.
Made-to-order and custom powder coat items show their lead time at the top of this page, right next to the truck icon. These are built fresh for you, so timing varies by brand and current backlog.
Need something by a specific date? Call us at 541-668-7503 before ordering and we will check stock and ETA on that exact part. We can often point you to an in-stock alternative from another distributor.
Questions? Contact us, we respond within 24 hours.
