Last Updated on October 11, 2025 by foysal islam
best big bore kit for 50cc scooter offers a powerful upgrade to enhance your scooter’s engine performance and speed. Whether you want more torque for hill climbing or higher top speeds, these kits provide a cost-effective way to boost your ride.
Ideal for scooter enthusiasts in the USA looking to improve engine displacement and overall power, these kits vary in valve size, compatibility, and included components. Choosing the right kit depends on your mechanical skill, budget, and scooter model.
Below is a quick comparison table to help you evaluate the top options, followed by detailed reviews to guide your purchase decision.
Quick Comparison: best big bore kit for 50cc scooter
| Product | Features | Best For | CTA |
|---|---|---|---|
| Glixal ATMT1-008 80cc Kit | 47mm Cylinder Upgrade Complete Rebuild Kit |
Best All-Around Upgrade | Check Price |
| Maoyubelt 47mm Big Bore Kit | Cylinder & Piston Rings Fits Many GY6 Models |
Best Budget Option | Check Price |
| Kymlaa 100cc Big Bore Kit | 69mm Valve Length Includes Racing CDI & Coil |
Best Performance Upgrade | Check Price |
| Glixal GY6 100cc Big Bore Kit | Large Valve Heads DLC Wear Resistant Rings |
Best for Acceleration | Check Price |
| Trkimal 100cc Big Bore Kit | 64mm Valve Length Complete Engine Upgrade |
Best for Speed & Torque | Check Price |
Our Top 5 best big bore kit for 50cc scooter
We selected five models for different needs and budgets, prioritizing feature quality, performance, fit/compatibility, reliability, and value.
Glixal ATMT1-008 80cc Kit
Overview
This kit suits riders wanting a reliable 80cc upgrade for most Chinese-made 50cc scooters and ATVs. It includes all necessary parts for a full top-end rebuild, boosting power and speed notably.
Fits GY6 50cc engines with a 47mm bore, compatible with brands like JONWAY and TAOTAO. Installation is straightforward, making it a solid choice for USA riders seeking performance and value.
Specs
→ Inner Diameter of Cylinder 47mm
→ Outer Diameter of Piston Pin 13mm
→ High Quality Durable Piston Rings
→ Includes Cylinder, Piston, Gaskets, Studs, and More
→ Fits GY6 49cc to 80cc Engines
Pros
👍 Quality construction and materials
👍 Noticeable power and speed gains
👍 Easy installation process
👍 Complete upgrade kit included
👍 Good value for money
Cons
👎 Mixed longevity reports
👎 Some users report durability issues
👎 Limited to GY6 50cc engine types
Customer Experience
Customers praise the easy installation and strong power boost, especially on hills. Some report excellent durability, while others experienced issues after extended use.
Best For
Best All-Around Upgrade
Maoyubelt 47mm Big Bore Kit
Overview
This budget-friendly kit offers a 47mm bore upgrade for GY6 50cc engines, including cylinder block, piston, rings, and gaskets. It fits many popular scooter models and is ideal for riders wanting a simple power boost.
Installation is straightforward, and the kit is designed to improve power and torque without major modifications, making it a practical choice for USA scooter owners.
Specs
→ Diameter 47mm (53.2mm)
→ Includes Cylinder Block and Piston
→ Complete Ring Set and Circlips
→ Two Head Gasket Sets Included
→ Fits GY6 Engine Clone 139QMB
Pros
👍 Easy installation
👍 Fits many scooter models
👍 Improves power and torque
👍 Complete kit included
👍 Affordable price point
Cons
👎 Limited detailed customer feedback
👎 No included ignition or clutch upgrades
👎 May require carb/exhaust tuning
Customer Experience
Users find it easy to install and report significant power improvements when paired with aftermarket exhausts. The kit wakes up the scooter’s performance noticeably.
Best For
Best Budget Option
Kymlaa 100cc Big Bore Kit
Overview
This comprehensive 100cc kit upgrades your GY6 50cc scooter with a 50mm bore and 69mm valve length. It includes racing CDI, ignition coil, spark plug, clutch springs, and full engine gaskets for a full performance rebuild.
Ideal for experienced mechanics in the USA, it offers a significant power and speed increase, though some report mixed results with the CDI module and spark plug quality.
Specs
→ Bore: 50mm Displacement: 100cc
→ Valve Length: 69mm
→ Includes Racing CDI and Ignition Coil
→ Full Set of Engine Gaskets Included
→ Comes with Clutch Springs and Spark Plug
Pros
👍 Easy installation with instructions
👍 Noticeable power and speed gains
👍 Complete performance upgrade kit
👍 Includes ignition and clutch parts
👍 Good value for money
Cons
👎 CDI module issues reported
👎 Some spark plug thread problems
👎 Mixed feedback on part quality
Customer Experience
Customers find the kit easy to install and appreciate the power boost. Some report issues with CDI functionality and spark plug quality, but overall performance is improved.
Best For
Best Performance Upgrade
Glixal GY6 100cc Big Bore Kit
Overview
This kit features large valve heads and DLC-coated piston rings for enhanced power and durability. It upgrades your GY6 50cc scooter to approximately 82cc with improved acceleration and hill climbing ability.
Installation is manageable for hobby mechanics in the USA, though some users report exhaust valve spring breakage and low-quality CDI and exhaust studs.
Specs
→ Large Valve Cylinder Head Assy 18.5/20.5mm
→ Compatible with 69mm Long Valve Heads
→ DLC Wear Resistant Piston Rings
→ Engine Side Cover Gasket for Short Case
→ Attention to Piston Marking Orientation
Pros
👍 Quality materials and coating
👍 Noticeable power and acceleration
👍 Straightforward installation
👍 Includes ignition and clutch upgrades
👍 Good value for price
Cons
👎 Exhaust valve spring breakage
👎 Low-quality CDI box
👎 Weak exhaust studs
Customer Experience
Users report great acceleration and power gains, but some experienced exhaust valve spring failure. The kit bolts on easily, though CDI and studs may need upgrading.
Best For
Best for Acceleration
Trkimal 100cc Big Bore Kit
Overview
This 100cc kit upgrades your GY6 50cc scooter with a 50mm bore and 64mm valve length. It includes a full engine rebuild set with racing CDI, ignition coil, spark plug, clutch springs, and roller weights for enhanced speed and torque.
Best suited for mechanically inclined riders in the USA, it requires proper tools and some experience for installation. Users recommend upgrading carburetor and exhaust for optimal performance.
Specs
→ Bore: 50mm Displacement: 100cc
→ Valve Length: 64mm
→ Includes Racing CDI and Ignition Coil
→ Full Engine Gasket Set Included
→ Comes with Clutch Springs and Roller Weights
Pros
👍 Easy installation with tutorials
👍 Strong acceleration improvements
👍 Complete upgrade kit
👍 Good value for money
👍 Quality parts and materials
Cons
👎 Mixed performance feedback
👎 Some missing gaskets reported
👎 CDI box issues noted
Customer Experience
Customers appreciate the acceleration gains and ease of installation but mention occasional missing parts and CDI box problems. Proper tool use and mechanical knowledge are advised.
Best For
Best for Speed & Torque
Buying Guide: best big bore kit for 50cc scooter
Engine Compatibility
Ensure the big bore kit matches your scooter’s engine model, typically GY6 50cc or clones. Check bore diameter and valve length specifications for proper fit.
Included Components
Look for kits that include all necessary parts like cylinder, piston, gaskets, and sometimes ignition and clutch upgrades. Complete kits simplify installation and improve reliability.
Installation Difficulty
Consider your mechanical skill level. Some kits require advanced tools and knowledge, while others are designed for easier installation with step-by-step guides.
Performance Goals
Decide if you want moderate power boosts or maximum speed and torque. Larger bore and valve sizes generally offer more performance but may need additional tuning.
Durability and Quality
Choose kits with high-quality materials such as DLC-coated piston rings and durable valves. Read customer reviews for insights on longevity and common issues.
FAQs: best big bore kit for 50cc scooter
What does a big bore kit do for a 50cc scooter?
It increases the engine’s cylinder diameter, boosting displacement and power for better acceleration and top speed.
Can I install a big bore kit myself?
Installation difficulty varies; some kits are beginner-friendly, but others require mechanical skills and special tools.
Will I need to upgrade other parts after installing a big bore kit?
Often yes; upgrading carburetor, exhaust, and variator helps optimize performance and prevent engine issues.
Are all big bore kits compatible with every 50cc scooter?
No, compatibility depends on engine type and model. Always verify specifications before purchase.
How much speed increase can I expect?
Speed gains vary by kit and setup but typically range from 10 to 20 mph over stock performance.
Do big bore kits affect fuel efficiency?
They may reduce fuel efficiency due to increased power output and fuel demand.
Is a bigger valve length better?
Larger valves can improve airflow and power but require matching components and proper tuning.
Final Verdict: best big bore kit for 50cc scooter
For balanced performance and ease of installation, the Glixal ATMT1-008 80cc Kit is a top pick. For maximum power and full engine upgrades, the Kymlaa 100cc Big Bore Kit offers the best performance. Budget-conscious riders will appreciate the Maoyubelt 47mm Big Bore Kit’s affordability and simplicity.
I am Jaxon Mike, the owner of the Rcfact website. Jaxon Mike is the father of only one child. My son Smith and me we are both RC lovers. In this blog, I will share tips on all things RC including our activities, and also share with you reviews of RC toys that I have used.