Looking to add displacement and horsepower to your dirt bike, ATV, or pit bike engine? A big bore kit can increase cylinder bore and overall displacement, improving torque and top-end pull. This guide highlights five well-suited options for common 90cc–125cc and 110cc engines, aimed at riders who want stronger acceleration, easier hill climbs, or boosted RPM stability. Each pick is best for different bike families, from Chinese 110cc dirt bikes to small-displacement scooters and go-karts. The table below summarizes the top choices.
| Product | Best For | |
|---|---|---|
| PowerMotor 52.4mm Cylinder Kit | 4-stroke horizontal 110cc ATV / dirt pit bikes | Direct big-bore replacement with gasket set and piston ring kit |
| Glixal 100cc Big Bore Kit | GY6-based scooters and go-karts | Larger valves for improved intake/exhaust flow |
| Anxingo 52.4mm Aluminum Kit | Chinese 90–125cc engines (ATV, dirt bike) | Aluminum construction for durability and cooling |
| ABCERRSI 52.4mm Big Bore Kit | 4-stroke 110cc Chinese Taotao/Coolster family | Complete kit with gasket set and hardware |
| Anfigo 52.4mm Kit | Taotao / Roketa / Coolster 110cc dirt bikes | Includes piston kit and head compatibility notes |
PowerMotor 52.4mm Big Bore Kit For 110cc Engines
Best for: Riders with 110cc horizontal engines in ATVs, dirt bikes, or go-karts who want a straightforward replacement that includes a complete cylinder head, piston ring kit, gaskets, and spark plug. This kit is designed for compatibility with a wide list of 110cc models.
Why selected: It focuses on a direct big-bore upgrade, offering essential components in one package, which reduces sourcing time. The bore size (52.4mm) is a common upgrade for 110cc platforms seeking more torque at low-to-mid RPMs.
Caution: Verify mounting hole spacings, intake/exhaust port diameters, and 47–45mm height tolerances to ensure proper fit for your exact model.
Glixal GY6 100cc Big Bore Cylinder Kit
Best for: Gy6-based scooters, go-karts, and light-duty ATVs that benefit from a larger valve head and higher displacement. This kit emphasizes valve size improvements for better airflow.
Why selected: The kit uses a larger 18.5/20.5mm valve head, which can improve breathing at higher RPMs and boost power output for urban riders or tight tracks.
Caution: If your original head uses smaller valves, you may need to swap rocker arms to match the larger valve dimensions for proper valve timing.
Anxingo 52.4mm Aluminum Big Bore Kit
Best for: Lifan 125cc and similar horizontal engines used in Chinese dirt bikes and ATVs where aluminum construction supports heat management and longevity.
Why selected: The aluminum construction helps with durability and consistent heat dissipation in high-rev environments, potentially reducing the risk of overheating during extended rides.
Caution: Confirm exact engine compatibility with your model (block height and mounting points) before ordering, as some variants require specific hardware or spacers.
ABCERRSI 52.4mm Big Bore Kit For 110cc Taotao/Coolster
Best for: 110cc Chinese Taotao, Coolster, SSR, Kazuma, and similar dirt bikes that use a 110cc horizontal engine architecture and require a full top-end overhaul.
Why selected: This kit includes a practical set of components (cylinder, head, piston ring kit, and gaskets) designed to fit a broad range of 110cc platforms, simplifying the rebuild process.
Caution: Double-check bore and piston diameters to ensure exact match with your engine model to prevent misfit or compression issues.
Anfigo 52.4mm Big Bore Kit For Taotao Roketa Coolster 110cc
Best for: Taotao, Roketa, and Coolster 110cc 4-stroke ATVs and dirt bikes requiring a reliable 52.4mm bore with an included piston kit and timing components.
Why selected: It provides a complete rebuild kit with the 52.4mm bore, piston, and timing drive sprocket, helping riders restore performance in one purchase.
Caution: The listing notes that it does not fit 125cc cylinder heads with large valves, so verify valve size compatibility before buying.
Buying Guide: Key Considerations For Choosing A Big Bore Kit
- Engine compatibility: Confirm bore diameter, stroke length, valve size, and mounting hole spacing for your specific model and year.
- Purpose and riding style: Choose larger bores for increased top-end power and sustained RPMs, or focus on torque improvements for hill-climbing stability.
- Material and durability: Aluminum components typically offer lighter weight and better heat dissipation, while forged or cast parts may differ in wear resistance.
- Included components: Look for kits that include gaskets, seals, timing sprockets, and rings to minimize additional purchases.
- Installation considerations: Some big bore kits may require head or rocker-arm adjustments, valve clearance checks, or fuel tuning after installation.
- Maintenance impact: Larger displacement can shift required maintenance intervals; plan for more frequent cooling checks and air-fuel adjustments if needed.
- Warranty and compatibility notes: Review model-specific notes about valve sizes, head compatibility, and potential need for aftermarket parts.
Frequently Asked Questions
- What is a big bore kit?
It is an upgrade that increases the cylinder bore to raise engine displacement, typically boosting torque and horsepower. - Will a big bore kit require engine tuning?
Yes. After installation, adjustments to timing, jetting, and air-fuel mixture may be needed for optimal performance. - Can I install a big bore kit myself?
It varies by model. Some kits are straightforward replacements, while others require mechanical expertise for precise clearances. - Which engine families are most compatible with a 52.4mm bore?
Many 90cc–125cc and 110cc horizontal engines across Taotao, Coolster, SSR, Kazuma, Lifan, and similar lines support 52.4mm bores. - Are bigger bores reliable for daily riding?
Reliability depends on proper installation, cooling efficiency, and maintenance. Aluminum and well-matched components help longevity. - Should I replace the entire top end or just the cylinder?
For significant wear or performance goals, a full top-end rebuild (cylinder, head, piston, gaskets) is often recommended.