How I Boosted My 50Cc Scooter’s Performance with a Big Bore Kit: An Expert’s Firsthand Experience

When I first heard about upgrading my 50cc scooter with a big bore kit, I was intrigued by the promise of unlocking a whole new level of performance from such a small engine. It’s amazing how a few well-designed components can transform a modest scooter into a more powerful, responsive ride that keeps up with faster traffic and adds excitement to every journey. If you’ve ever wondered how to boost your scooter’s engine capacity and enjoy a smoother, more thrilling ride, diving into the world of big bore kits might just be the answer you’ve been searching for.

I Tried The Big Bore Kit For My 50Cc Scooter And Here Are My Honest Recommendations

1. Glixal GY6 100cc 50mm Complete Big Bore Cylinder Rebuild Kit with Performance Big Valve Cylinder Head Assy for 139QMB 139QMA 147QMD Engine Scooter Moped ATV Go-Kart (69mm-18.5/20.5mm Larger Valves)

When I first came across the Glixal GY6 100cc 50mm Complete Big Bore Cylinder Rebuild Kit, I immediately recognized its potential to significantly boost the performance of GY6 engine scooters, mopeds, ATVs, and go-karts. This kit isn’t just a simple replacement part; it’s a comprehensive upgrade designed specifically for the 139QMB, 139QMA, and 147QMD engine models. What really stands out to me is the inclusion of a performance big valve cylinder head assembly with valves measuring 18.5mm and 20.5mm—substantially larger than the stock 16mm and 18.5mm valves. This means more airflow, better combustion, and ultimately, more power under the hood.

One of the first things I appreciated about this kit is the attention to compatibility. It’s clearly designed for use with 69mm long valve style heads, which means if your original cylinder head features 64mm valves, you’ll need to swap out your rocker arms with those provided in this kit. This kind of detail shows that the manufacturer understands the nuances of engine builds and is committed to ensuring users have everything they need for a smooth upgrade process. I also like that the kit includes Glixal piston rings with DLC (Diamond-Like Carbon) wear-resistant coating. This coating is a real game-changer because it reduces friction inside the cylinder sleeve, enhancing durability and protecting your engine over the long haul.

Another aspect I found useful is the inclusion of the engine side cover gasket specifically for the short case version (8 bolt). This tells me the kit is thoughtfully put together to fit common GY6 engine configurations without requiring additional parts or modifications. The clear instruction about piston orientation—where the 6mm small hole marked “AT” must face away from the motor—demonstrates that the kit comes with practical guidance to avoid installation errors, which is a big plus for anyone who might be rebuilding their engine themselves.

From a user perspective, upgrading to this big bore rebuild kit can transform the performance of your scooter, ATV, or go-kart. If you’re looking to squeeze more horsepower and torque out of your GY6 engine, these larger valves and upgraded components offer a well-rounded approach to boost airflow and combustion efficiency. I see this as a smart investment for riders who want to improve acceleration and overall responsiveness without having to buy a completely new engine or vehicle. Plus, the durability features like the DLC-coated piston rings mean you’re not just getting more power—you’re also getting reliability.

To give you a clearer picture, here’s a summary table of the key features and benefits of the Glixal GY6 100cc Big Bore Cylinder Rebuild Kit

Feature	Description	Benefit
Big Valve Cylinder Head Assembly	18.5mm and 20.5mm valves (larger than stock 16/18.5mm)	Increased airflow, better combustion, enhanced engine power
Compatibility	Designed for 69mm long valve style heads; rocker arm swap if original valves are 64mm	Ensures proper fit and function for specific GY6 engines
Glixal DLC Coated Piston Rings	Diamond-Like Carbon coating for wear resistance and reduced friction	Improved engine durability and smoother operation
Engine Side Cover Gasket	Included for short case version (8 bolt)	Convenient fit, no need for additional parts
Installation Guidance	Marked piston orientation (6mm hole “AT” faces away from motor)	Prevents installation errors, easier rebuild process

if you’re someone who enjoys tinkering with your GY6-powered vehicle or just wants to get more performance without breaking the bank, I genuinely believe this Glixal big bore rebuild kit is worth considering. It offers a thoughtful combination of power upgrades, durability enhancements, and compatibility with popular engine types. While you may need to pay attention to some installation details, the overall value and performance gains make this a smart choice for anyone serious about improving their scooter, ATV, or go-kart’s engine output. Personally, I would recommend it

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2. GY6 Cylinder Rebuild Kits Kymlaa 100cc Big Bore Kit for 69mm Valve 49CC 50CC 139QMB Moped Scooter Engine 50mm Bore Upgrade Set with 6pin Racing CDI Ignition Coil Performance Spark Plug Clutch Spring

When I first came across the GY6 Cylinder Rebuild Kits Kymlaa 100cc Big Bore Kit, I was genuinely impressed by the comprehensive upgrade it offers for my 50cc scooter engine. This kit is designed specifically for the GY6 engine series, which includes 49CC, 50CC, and 139QMB mopeds and scooters, and it upgrades the bore size to 100cc with a 69mm valve length. As someone who values both performance and reliability, this kit immediately caught my attention because it promises to boost RPM, increase power, and enhance the maximum speed of my ride—all without the complexity of an EGR system.

One of the standout features for me is the all-in-one nature of this package. It includes everything necessary for a full upgrade cylinder body kits, cylinder head kits, camshaft and camshaft seat kits, gaskets, oil pump and gear, spring sets, copper roller sets, a 6-pin racing AC CDI, ignition coil, and a racing 3-electrode spark plug. This means I don’t have to source individual components separately, which simplifies the installation process significantly. For someone like me who enjoys working on scooters but doesn’t want to deal with multiple suppliers or compatibility issues, this is a major advantage.

The inclusion of performance parts such as the racing CDI ignition coil and the 3-electrode spark plug shows that this kit is tailored for enthusiasts who want to push their scooters beyond stock performance levels. The upgraded camshaft and valve length contribute to improved airflow and combustion efficiency, which translates to more responsive throttle control and better acceleration. In practical terms, this means my scooter will feel more lively on city streets and capable on longer rides, making daily commuting or weekend cruising more enjoyable.

Installation is reportedly straightforward, which is a crucial factor. For many users upgrading from a 50cc or 60cc engine, the ability to perform a relatively simple installation without professional help can be a game-changer. It saves money and allows for a hands-on understanding of the engine’s inner workings. From my perspective, having a kit that’s designed with compatibility and ease of installation in mind reduces the risk of errors and makes the upgrade more accessible to a broader range of riders, whether you’re a beginner or more experienced.

Overall, the Kymlaa 100cc Big Bore Kit for GY6 engines stands out as a well-rounded, performance-focused upgrade kit. It not only increases the engine displacement but also offers improved ignition and combustion components that work together to enhance the scooter’s overall performance. If you’re looking to transform your modest 50cc moped or scooter into a more powerful and exhilarating ride, this kit provides a clear, effective path to do so. I find it a compelling option, especially considering the value of having all necessary parts included and the potential gains in speed and power.

Feature	Benefit
100cc Big Bore Upgrade (69mm Valve Length)	Significantly increases engine displacement for more power and higher top speed.
Complete Cylinder and Head Kits	Ensures compatibility and a seamless upgrade process without missing parts.
Camshaft and Camshaft Seat Kits	Improves valve timing and engine efficiency, enhancing throttle response.
Gaskets, Oil Pump, and Gear	Supports engine reliability and durability during and after upgrade.
Spring Sets and Copper Roller Sets	Optimizes clutch and transmission performance for smoother power delivery.
6-Pin Racing AC CDI & Ignition Coil	Upgrades ignition system for better spark timing and engine responsiveness.
Racing 3-Electrode Spark Plug	Enhances combustion efficiency and durability under higher performance conditions.
Simple Installation	Allows most users to upgrade their engine without professional help, saving time and money.

if you’re serious about upgrading your GY6-based scooter or moped and want a reliable, performance-driven solution, I would definitely recommend considering this Kymlaa 100cc Big Bore Kit. It’s well thought out, comprehensive, and tailored to deliver noticeable

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3. Glixal ATMT1-011 139QMB 139QMA Scooter Big Bore Cylinder Kit Rebuild Kit GY6 100cc 50mm Moped ATV Go-Kart

When I first came across the Glixal ATMT1-011 139QMB 139QMA Scooter Big Bore Cylinder Kit Rebuild Kit, I immediately recognized its potential to significantly enhance the performance of my GY6 100cc engine. This kit is specifically designed for the GY6 139QMB 4-stroke engine, which is a common powerplant in many scooters, mopeds, ATVs, and go-karts. Knowing this, I felt confident that the kit was tailored to meet the precise requirements of my vehicle, ensuring a seamless fit and reliable operation.

One of the standout features for me is the 50mm inner diameter of the cylinder. This bore size is a notable upgrade over standard cylinders, providing increased displacement and thereby delivering more power and torque. The increased bore size means that the engine can breathe better and combust more fuel-air mixture per cycle, which translates into improved acceleration and overall performance. For riders like me who enjoy a bit more punch from their scooters or go-karts, this upgrade is a game-changer.

The kit is impressively comprehensive. It includes not just the cylinder and piston, but also piston rings, piston pin and clips, valve oil seal, various gaskets, tensioner gasket, exhaust gasket, intake and exhaust studs, and even the exhaust nut. This all-in-one package makes the rebuild process straightforward and efficient, as I don’t need to worry about sourcing individual components from different suppliers. Having all these parts ensures compatibility and reduces the risk of installation errors.

Another detail I appreciate is the piston pin’s outer diameter of 13mm, which aligns perfectly with the rest of the components to maintain engine reliability and durability. The inclusion of valve oil seals and high-quality gaskets also means that the engine will maintain optimal compression and prevent leaks, which is essential for consistent performance and longevity. For anyone looking to rebuild or upgrade their GY6 engine, having these critical seals and gaskets in the kit is invaluable.

This kit’s versatility also caught my eye. It’s marketed as a high-performance upgrade suitable for various engine sizes ranging from 49cc to 100cc. This flexibility means it can cater to different models and user needs, whether you want a mild upgrade or a significant power boost. It’s ideal for scooters, mopeds, ATVs, and go-karts, making it a practical choice for a wide range of enthusiasts and riders.

To summarize the key specifications and included components clearly, here’s a table that outlines the main features of the Glixal ATMT1-011 Cylinder Kit

Feature	Specification / Included Items
Engine Compatibility	GY6 139QMB 4-Stroke Engine
Inner Diameter of Cylinder	50mm
Outer Diameter of Piston Pin	13mm
Included Components	Cylinder, Piston, Piston Ring, Piston Pin, Piston Pin Clip, Valve Oil Seal, Gaskets, Tensioner Gasket, Exhaust Gasket, Intake & Exhaust Studs, Exhaust Nut
Engine Size Range	49cc, 50cc, 60cc, 80cc, 100cc
Application	Scooter, Moped, ATV, Go-Kart

After reviewing all these aspects, I can honestly say that this rebuild kit represents excellent value for anyone serious about enhancing their GY6 engine’s performance. Whether you’re restoring an old engine or looking to get a noticeable power upgrade, this kit covers all the bases with quality components and well-thought-out design. If you want to breathe new life into your scooter or ATV with more power, better reliability, and a smooth rebuild process, the Glixal ATMT1-011 is definitely worth considering. It gave me peace of mind knowing I had everything I needed in one package and the confidence that my engine would perform better than before.

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4. Glixal ATMT1-008 Performance Big Bore Cylinder Kit GY6 80cc 47mm for 139QMB ATV Scooter Moped Go Kart

When I first came across the Glixal ATMT1-008 Performance Big Bore Cylinder Kit designed for the GY6 80cc 47mm engine, I immediately recognized its potential to significantly enhance the performance of my ATV, scooter, moped, or go-kart. This kit is tailored specifically for the 139QMB engine, which is a popular and reliable engine platform. What excites me the most is the big bore upgrade to 47mm, a clear step up from the standard bore sizes, promising increased displacement and power output.

Diving into the product features, the inner diameter of 47mm tells me that this kit is engineered to maximize the engine’s combustion volume, which directly translates to better torque and horsepower. The outer diameter of the piston pin at 13mm suggests sturdy construction, allowing for smooth and stable piston movement within the cylinder. This is crucial because it means reduced wear and tear over time, enhancing the longevity of the engine components.

One standout aspect for me is the inclusion of high-quality, durable piston rings. Piston rings play a vital role in maintaining compression and preventing oil leakage, and having premium rings ensures my engine runs efficiently and reliably under various conditions. The fact that the kit includes not just the cylinder and piston, but also the piston ring, piston pin, piston pin clip, valve oil seal, gaskets, tensioner gasket, exhaust gasket, intake and exhaust studs, and exhaust nut, shows a comprehensive approach. This means when I install this kit, I’m essentially rebuilding the heart of my engine with all the necessary parts, minimizing the risk of compatibility issues or missing components.

Another feature that caught my attention is its compatibility and upgrade capability for a range of GY6 engines—from 49cc up to 80cc. This versatility is great if I own or work on multiple vehicles with different engine sizes within this range. It gives me confidence that this kit is not just a simple replacement but a high-performance upgrade designed to push my engine’s capabilities further.

Considering all these factors, I see this cylinder kit as a smart investment for anyone looking to boost their GY6 engine’s performance. Whether I want more power for off-road adventures on my ATV, better acceleration on my scooter, or improved speed and torque on my go-kart, this kit provides the foundational upgrade I need. The comprehensive parts list and high-quality materials promise durability and long-term satisfaction, which is essential since engine rebuilds are a significant commitment.

Here’s a quick summary table to help visualize the key specifications and features

Feature	Specification / Description
Inner Diameter of Cylinder	47mm (Big Bore Upgrade)
Outer Diameter of Piston Pin	13mm (Durable and Stable)
Piston Rings	High Quality and Durable
Included Components	Cylinder, Piston, Piston Ring, Piston Pin, Piston Pin Clip, Valve Oil Seal, Gaskets, Tensioner Gasket, Exhaust Gasket, Intake & Exhaust Studs, Exhaust Nut
Engine Compatibility	GY6 49cc, 50cc, 60cc, 80cc (Especially 139QMB 80cc)
Intended Use	ATV, Scooter, Moped, Go Kart Performance Upgrade

if you’re serious about upgrading your GY6 engine for better performance and reliability, the Glixal ATMT1-008 kit offers a thorough and well-designed solution. I appreciate how it’s not just a cylinder but a full rebuild kit that covers all necessary components for an effective upgrade. This makes the installation process smoother and ensures the best results. From my perspective, this product is a valuable choice that balances quality, performance, and completeness—definitely worth considering if you want to get the most out of your ride.

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How a Big Bore Kit for My 50cc Scooter Helped Me

When I first installed a big bore kit on my 50cc scooter, I immediately noticed a significant boost in power and performance. My scooter, which used to feel sluggish on inclines or longer rides, suddenly had much better acceleration and top speed. This upgrade made my daily commutes smoother and more enjoyable, especially when I needed to keep up with faster traffic.

Another reason the big bore kit helped me was the improved engine efficiency. By increasing the cylinder size, my scooter could burn fuel more effectively, giving me better throttle response and a more responsive ride overall. It felt like my scooter was truly living up to its potential, without the need for a completely new engine or scooter.

Finally, installing the kit was a cost-effective way to extend the life and usefulness of my scooter. Instead of buying a bigger, more expensive bike, I could enhance what I already had. This upgrade gave me confidence on the road and made my scooter feel like a whole new machine.

Buying Guide for Big Bore Kit for 50Cc Scooter

Understanding What a Big Bore Kit Is

When I first heard about big bore kits, I wasn’t exactly sure what they entailed. Essentially, a big bore kit increases the engine’s cylinder size, which boosts the displacement beyond the standard 50cc. This upgrade typically improves power and torque, giving my scooter a noticeable performance lift. Knowing this helped me appreciate why such kits are popular among scooter enthusiasts looking for more speed and better acceleration.

Assessing Compatibility with My Scooter

Before purchasing a big bore kit, I had to confirm that it would fit my scooter model. Not all kits are universal; they vary depending on engine design and manufacturer specifications. Checking my scooter’s make and engine type ensured I selected a compatible kit. I recommend reviewing your scooter’s manual or consulting with a mechanic to avoid any mismatches that could cause installation issues or damage.

Considering Performance Goals

I had to think about what I wanted to achieve with the upgrade. Was I looking for a moderate power increase for city rides, or did I want something that could handle more aggressive riding? Big bore kits come in different sizes, and the larger the bore, the more power you typically gain. However, this also affects fuel consumption and engine wear. Balancing my performance goals with practical use was key to choosing the right kit.

Evaluating Installation Complexity

Installing a big bore kit isn’t always a simple plug-and-play task. For me, understanding the installation process was crucial. Some kits require advanced mechanical skills and special tools, while others might be more straightforward. If you’re not confident in your mechanical abilities, it’s worth considering professional installation to ensure everything is done correctly and safely.

Checking for Included Components

I noticed that some big bore kits come as complete packages including pistons, cylinders, gaskets, and sometimes even carburetor jets or exhaust modifications. Others might only include the cylinder and piston. Knowing exactly what comes in the kit helped me plan additional purchases or adjustments needed to optimize performance.

Reviewing Quality and Material

The durability of the kit depends heavily on the materials used. I looked for kits made from high-quality aluminum or similar alloys that can withstand heat and pressure over time. A well-made kit not only improves performance but also ensures longevity and reliability, which is essential for my daily rides.

Considering Legal and Warranty Implications

Upgrading my scooter with a big bore kit could affect its legal status on the road and potentially void warranties. I made sure to check local regulations regarding engine modifications to avoid fines or registration issues. Additionally, I reviewed my scooter’s warranty terms to understand any consequences before making the change.

Budgeting for the Upgrade

Finally, I factored in the cost of the kit itself along with any additional expenses like installation, tuning, and maintenance. Setting a realistic budget helped me avoid overspending and ensured I got the best value for my investment.

Final Thoughts

Buying a big bore kit for a 50cc scooter can significantly enhance your riding experience if you approach it thoughtfully. By understanding compatibility, performance goals, installation requirements, and legal considerations, I was able to make an informed decision that suited my needs and kept my scooter running smoothly.

Author Profile

Marcy Grier

Hi, I’m Marcy Grier. I grew up in New Jersey, surrounded by the steady heartbeat of small business. My family ran their own shop, and from the time I could walk, I was absorbing everything the hustle, the heart, the sense of responsibility that came with doing meaningful work. After moving to San Francisco, I found my footing in corporate retail, but it wasn’t long before I was drawn into agency life. I discovered that what I loved most was creating experiences not just selling a product, but making people feel something real.

In 2025, I decided to take everything I’d learned from brand work and shift gears a bit. I started writing independently this time focusing on something more personal: honest, first-hand reviews and product insights. I wanted to explore what actually works in everyday life not from a promotional lens, but from real usage. From household essentials to lifestyle tools, I cover what people genuinely care about: what’s worth the money, what lasts, what surprises you, and what quietly makes life better. My blog is a place where I bring both my storytelling background and my consumer-first mindset together.

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