GOOFIT
56mm Engine Cylinder & Piston Rebuild Kit for YX140 1P56FMJ 140cc 150cc Dirt Pit Bike ATV
56mm Engine Cylinder & Piston Rebuild Kit for YX140 1P56FMJ 140cc 150cc Dirt Pit Bike ATV
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Product Overview
Unlock the raw power of your YX engine with the GOOFIT 56mm Cylinder Rebuild Kit. Engineered specifically for the YX140 (1P56FMJ) and compatible 150cc oil-cooled horizontal engines, this kit is designed to restore lost compression and maximize torque. With an optimized combustion chamber profile and high-temperature stable materials, it delivers a significant boost in throttle response and overall mechanical reliability for your pit bike or quad.
Product Compatibility
This 56mm kit is a high-performance replacement for YX (YinXiang) style horizontal engines.
| Engine Model | Displacement | Vehicle Type |
| YX140 / 1P56FMJ | 140cc | Dirt Bikes, Pit Bikes |
| Compatible Horizontal | 150cc Variants | ATVs, Quads, Karts |
| Piston Style | 56mm Bore | High-Compression Ready |
Specifications
| Attribute | Details |
| Cylinder Inner Diameter | 56mm / 2.2" |
| Engine Code | YX140 / 1P56FMJ |
| Engine Type | 4-Stroke Oil-Cooled / Air-Cooled |
| Displacement | 140cc - 150cc |
| Package Includes | Cylinder, Piston, Rings, Pin, Clips, Gaskets |
Key Features
- YX140 Precision Fit: Tailor-made for the 1P56FMJ engine series, ensuring perfect oil passage alignment and deck height for optimal valve-to-piston clearance.
- Enhanced Compression Ratio: Featuring an optimized piston and combustion chamber design that improves thermal efficiency, resulting in more explosive power and a smoother RPM curve.
- Superior Thermal Stability: Constructed from advanced alloys with excellent corrosion resistance, this kit maintains structural integrity even under the high-stress conditions of off-road racing.
- Rigorous Quality Testing: Every cylinder undergoes strict dimensional inspection and leak testing to ensure "out-of-the-box" reliability and consistent performance.
- Optimized Scavenging: The precision-honed cylinder walls facilitate superior oil film retention and piston ring sealing, reducing blow-by and extending engine life.
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Fitment FAQ
Will this part fit my specific model and year?
This cylinder piston kit is intended for This 56mm kit is a high-performance replacement for YX (YinXiang) style horizontal engines.; Engine Model; Displacement; Vehicle Type; YX140 / 1P56FMJ; 140cc; Dirt Bikes, Pit Bikes. Key physical/spec details from the product data include 56mm Bore, Cylinder Inner Diameter: 56mm / 2.2", 56mm. Use the compatibility table and product photos together before ordering.
Do I need to match the OEM part number?
Yes. If your original part has a stamped OEM or manufacturer number, match that number first before ordering. For this cylinder piston kit, also compare the bore diameter, piston-pin size, gasket pattern, stud spacing, engine code, stroke type, and cylinder height. This is especially important for YX140 models because similar model names can use different parts by year or trim.
What models or situations does this part not fit?
Do not order this cylinder piston kit for machines outside the listed compatibility, or for units with different bore sizes, piston-pin diameters, stroke lengths, stud spacing, or gasket patterns. Do not rely only on the model name or engine size.
What should I check before ordering?
Before ordering, compare your original part with the photos and check the bore diameter, piston-pin size, gasket pattern, stud spacing, engine code, stroke type, and cylinder height. Recheck listed specs such as 56mm Bore, Cylinder Inner Diameter: 56mm / 2.2", 56mm. If any connector, mounting point, size, or year detail is different, confirm fitment before installation.