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United Express Distribution  |  SKU: CYLD-0078

50mm Big Bore Cylinder with Gasket for GY6 50cc-80cc 4-Stroke Scooters and Mopeds

Regular price $18.00
Shipping calculated at checkout.


Pickup available at 2875 N Berkeley Lake Rd NW, Suite 4

Usually ready in 1 hour

Will it fit your machine?

Not sure? Text or email a photo of your old part or your engine model number. We'll confirm it fits before you buy.

Delivery and Shipping

Ships from our Duluth, Georgia warehouse.

Most in-stock orders ship the same business day. UPS orders placed before 3:00 PM ET, USPS orders before 12:00 PM ET. After the cutoff, they go out the next business day.

Standard delivery runs 2 to 6 business days to most US addresses. US territories take 7 to 14. These are carrier estimates, not guarantees.

Free shipping on most parts, no minimum order. Oversized items (body kits, wheels, tires, batteries, and engines) are quoted to your address and shown at checkout before you pay.

We ship UPS and USPS, and email your tracking number as soon as the order leaves.

Questions? Call or text 404-532-9833. Full details on our Shipping page.

Description

Upgrade the engine of your ride with the 80cc Big Bore Cylinder Kit, engineered for GY6 50cc engine platforms commonly found in scooters, mopeds, and ATVs. This high-performance upgrade is precision-machined to deliver increased displacement, significantly enhancing horsepower, torque, and overall engine responsiveness. Whether you're looking to boost acceleration, climb steeper inclines, or simply cruise at higher top speeds, this cylinder upgrade ensures your engine performs beyond standard limits. Ideal for both everyday commuting and adventurous off-road riding, it brings race-inspired performance to your daily ride.

Crafted from durable, heat-resistant materials, the cylinder is built to endure high-RPM conditions and extended use. Designed specifically for the 139QMB (GY6 50cc) engine architecture, this 80cc upgrade is compatible with popular Chinese-made brands and models, including TaoTao, Jonway, Roketa, Peace, Baotian, Znen, and more. With a bore size of approximately 47mm–50mm (varies by kit variation), this cylinder offers improved combustion efficiency and fuel utilization. The package typically includes the cylinder block only (no piston or gaskets), making it ideal for customers who already have other top-end components or are customizing their build. Ensure proper clearance and installation by verifying your engine type before ordering.
  • Perfect Fit: This precision-machined cylinder offers a seamless fit for GY6 50cc-80cc engines, making it an ideal upgrade for Chinese scooters, go-karts, and ATVs. Compatible with models like YERFDOG, SYM, KYMCO, ROKETA, VENTO, and SUNL, it ensures easy integration into a wide range of motorized vehicles.
  • Wide Compatibility: Whether you're working with a scooter, go-kart, ATV, or mini dune buggy, this 80cc cylinder is made for you. It fits most Chinese 4-stroke 139QMB engines and is compatible with popular brands like WILDFIRE, STRADA, FUJI, and KAZUMA, making it a versatile option for engine upgrades.
  • High Performance: Experience a noticeable power increase with the 80cc Big Bore Cylinder. Designed for 4-stroke GY6 139QMB engines, the 47mm (53.2mm) bore transforms your standard 50cc into a performance-driven 80cc engine. Perfect for riders seeking enhanced speed, torque, and fuel efficiency without a full engine swap.
  • Durable Construction: Built from durable, heat-resistant aluminum alloy, this BBK cylinder is engineered to withstand high RPMs and tough riding conditions. The robust construction helps reduce engine wear, supports longer engine life, and ensures smoother, more reliable performance under pressure.
  • Easy Installation: Designed for convenience, the Cylinder is ideal for both mechanics and DIY riders. With basic tools and mechanical knowledge, you can install this BBK cylinder with ease. Its plug-and-play nature allows for fast upgrades, letting you hit the road or trail with more power in no time.
Specs:
  • Engine Compatibility: GY6 139QMB / QMB139 4-stroke engines
  • Bore Diameter: 50mm
  • Material: Aluminum alloy with cast iron liner
Known to Fit:
  • TaoTao (ATM50-A1, CY50-A), Jonway, Roketa (MC-08, MC-17), Peace Sports, Baotian, Znen, Baccio, Tank Urban 50, Kymco Agility 50 (Chinese clone), Wildfire, Kazuma, SUNL, and other GY6 50cc-based models.

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