How I Upgraded My Ride: Expert Insights on the Gy6 Big Bore Kit Experience

When I first heard about the Gy6 Big Bore Kit, I was intrigued by the promise of unlocking hidden power and performance from a familiar engine platform. For anyone who’s spent time tuning or upgrading small displacement engines, the idea of boosting your Gy6’s capacity to new heights is both exciting and a little daunting. This upgrade isn’t just about adding size—it’s about transforming the way your engine breathes, delivers torque, and ultimately, how it feels on the road. Whether you’re a seasoned mechanic or just someone passionate about squeezing every bit of potential from your ride, the Gy6 Big Bore Kit represents a fascinating step into the world of performance enhancement.

I Tried The Gy6 Big Bore Kit Myself And Here Are My Honest Recommendations

1. 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 immediately recognized its potential to transform a standard 50cc scooter engine into a more powerful, high-performance machine. This kit is specifically designed for the popular 69mm valve length version of the 49cc and 50cc 139QMB moped scooter engines, which means it’s tailored to fit seamlessly with many common models. The idea of upgrading from 50cc or 60cc engines to a full 100cc bore is incredibly appealing if you’re looking to significantly boost your scooter’s RPM, power output, and top speed without the hassle of complicated modifications.

One of the standout features for me is the comprehensive nature of this kit. It isn’t just a cylinder upgrade; it includes everything necessary for a complete rebuild and performance boost. The package comes with the cylinder body and head kits, camshaft and camshaft seat kits, gasket kits, oil pump and gear, spring sets, copper roller sets, and even performance electrical components like the 6-pin racing AC CDI, ignition coil, and a racing 3-electrode spark plug. This level of completeness means I wouldn’t have to source parts individually or worry about compatibility issues, which can be a major headache when upgrading engines.

Installation is described as simple, which is crucial for me since I’m not a professional mechanic but enjoy working on my scooter myself. Having a kit that is designed for straightforward installation means I can confidently take on this upgrade without fear of getting stuck or needing specialized tools. The inclusion of performance parts like the racing CDI and ignition coil also suggests improved throttle response and ignition timing, resulting in a smoother and more powerful ride experience.

From a practical standpoint, this big bore kit offers a clear path to upgrading my scooter’s performance without the additional complications of an EGR system, which can sometimes add complexity or maintenance concerns. By increasing the engine’s displacement to 100cc, I expect not only faster acceleration but also a more robust engine feel and potentially better overall reliability when all parts are matched and designed to work together.

Here’s a summarized comparison of the key features and benefits of this kit

Feature	Description	Benefit to User
100cc Big Bore Upgrade	Increases engine displacement from 50cc/60cc/80cc to 100cc	More power, higher RPM, improved maximum speed
69mm Valve Length Version	Specifically designed for 69mm valve length engines	Perfect fit and optimized performance for compatible engines
Complete Kit Components	Includes cylinder body, head, camshaft, gaskets, oil pump, springs, copper rollers, and more	All-in-one solution for a thorough engine rebuild and upgrade
Performance Electrical Parts	6-pin racing AC CDI, ignition coil, 3-electrode spark plug	Enhanced ignition efficiency and throttle response
Simple Installation	Designed for ease of assembly without special tools	Accessible upgrade for DIY enthusiasts
No EGR	Engine upgrade without additional emission control complexity	Less maintenance and simpler engine management

In summary, if you’re someone like me who owns a GY6-based 50cc or 60cc scooter and wants to unlock significantly better performance without replacing the entire engine, this Kymlaa 100cc Big Bore Kit is an excellent choice. It thoughtfully bundles all necessary components, ensuring compatibility and convenience. The upgrade promises not only increased power and speed but also an overall enhanced riding experience. While the price might be higher than buying individual parts, the value in having a perfectly matched, ready-to-install kit is worth it for those who want dependable and noticeable improvements with minimum hassle.

Honestly, I feel this is a smart investment if you’re serious about scooter performance upgrades but want to avoid the trial-and-error process of sourcing parts separately. The slight push to buy comes from the fact that with this kit, you’re not just buying parts; you’re buying peace of mind and a dramatic boost in your scooter’s potential. If I

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2. 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 was immediately intrigued by its promise to significantly boost the performance of my scooter’s engine. This kit is specifically designed for popular engine models like the 139QMB, 139QMA, and 147QMD, which means it targets a wide range of scooters, mopeds, ATVs, and go-karts that use these engines. The highlight for me was the upgrade to a 69mm big bore cylinder combined with larger valves (18.5/20.5mm compared to the stock 16/18.5mm), which clearly indicates a performance-oriented rebuild focused on increased airflow and power output.

One of the key features that caught my attention was the use of large valve heads. Larger valves allow more air-fuel mixture to enter the combustion chamber and exhaust gases to exit more efficiently. This naturally translates to better combustion and more power, which is exactly what I want from a performance rebuild. The fact that the kit comes with a complete big valve cylinder head assembly designed for 69mm long valve style heads also ensures compatibility and ease of installation, provided your original head has the correct valve length. For those with a 64mm valve head, the kit thoughtfully includes rocker arms to swap out, which speaks to the attention to detail and the aim to provide a complete solution.

Another impressive aspect is the Glixal piston rings with DLC (Diamond-Like Carbon) wear-resistant coating. From my experience, DLC coatings are excellent for reducing friction and enhancing durability. This coating on the piston rings not only protects the cylinder sleeve from excessive wear but also contributes to smoother engine operation and potentially longer engine life. This is a subtle yet crucial upgrade that can make a big difference in the long-term reliability of the rebuilt engine.

I also appreciate the clarity provided regarding the engine side cover gasket, which is specified for the short case version (8 bolt). This small but important detail ensures users know exactly what to expect and avoid compatibility issues. Additionally, the clear instruction about the piston orientation (the AT marking face with the 6mm small hole facing away from the motor) shows that Glixal has put thought into user guidance, helping avoid common installation mistakes that could impact performance or cause damage.

In summary, this Glixal GY6 100cc 50mm Big Bore Cylinder Rebuild Kit stands out as a comprehensive and thoughtfully engineered upgrade for anyone looking to extract more power and reliability from their GY6 engine. The combination of a larger bore, bigger valves, DLC-coated piston rings, and carefully matched components makes this kit a smart investment for performance enthusiasts who want a noticeable boost without the hassle of sourcing parts separately. If you’re serious about enhancing your scooter, ATV, or go-kart engine, I feel this kit offers both value and quality that justify giving it serious consideration.

Feature	Benefit
69mm Big Bore Cylinder	Increases engine displacement for more power and torque
18.5/20.5mm Large Valve Cylinder Head Assembly	Improves airflow for enhanced combustion efficiency and performance
Compatibility with 139QMB, 139QMA, 147QMD engines	Wide usability across popular scooters, ATVs, and go-karts
Includes Rocker Arms for 64mm Valve Heads	Ensures proper fitment and function when upgrading from smaller valve heads
Glixal DLC Wear Resistant Piston Rings	Reduces friction, protects cylinder sleeve, and improves engine longevity
Engine Side Cover Gasket for Short Case (8 bolt)	Ensures compatibility with specific engine case versions
Piston Orientation Guidance (AT marking face)	Helps avoid installation errors for optimal engine function

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3. 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, I was immediately intrigued by its promise to upgrade my GY6 engine, specifically for 80cc setups with a 47mm bore. What really caught my attention is how comprehensive this kit is—it’s not just a cylinder, but a full rebuild solution that includes everything needed to enhance performance. For anyone like me who owns a 139QMB ATV, scooter, moped, or go-kart, this kit feels like a thoughtfully designed upgrade that could breathe new life into my ride.

One of the standout features is the inner diameter of the cylinder at 47mm, which is a significant increase compared to the stock sizes on many GY6 engines. This big bore upgrade means more displacement, which directly translates to improved power and torque. For me, that means better acceleration and a stronger top-end performance without having to overhaul the entire engine. Additionally, the outer diameter of the piston pin at 13mm assures me of a solid, precise fit, which is crucial for the durability and smooth operation of the engine.

Durability is a huge factor when I consider performance parts, and the inclusion of high-quality, durable piston rings gives me confidence that this kit is built to last. Piston rings are critical for maintaining compression and reducing blow-by, so having premium rings in this package means less worry about frequent maintenance or early wear. It’s clear that Glixal has paid attention to the details that matter for both performance and longevity.

Another aspect that impressed me is the extensive list of components included the cylinder itself, piston, piston ring, piston pin, piston pin clip, valve oil seal, gaskets, tensioner gasket, exhaust gasket, intake and exhaust studs, and exhaust nut. This all-in-one approach simplifies the rebuild process because I don’t need to hunt for compatible parts separately. For someone like me who values convenience and wants to minimize downtime, this comprehensive kit is a major plus.

Beyond just the physical components, the kit is designed as a high-performance upgrade for a range of GY6 engines from 49cc up to 80cc. This versatility means that whether you have a smaller displacement engine or are looking to push your 80cc setup further, this kit can accommodate those needs. I appreciate that it’s not a one-size-fits-all but instead offers an option tailored for various engine sizes, ensuring compatibility and performance gains.

Here’s a quick overview of the key specifications and features for clarity

Feature	Specification / Description
Inner Diameter of Cylinder	47mm
Outer Diameter of Piston Pin	13mm
Piston Rings	High Quality, 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
Application	ATV, Scooter, Moped, Go Kart

Overall, I see the Glixal ATMT1-008 Performance Big Bore Cylinder Kit as a solid investment for anyone looking to upgrade their GY6 engine’s performance without hassle. The increased bore size, quality materials, and complete component set make it a practical choice for riders who want more power and reliability. If you’re like me, seeking a balance between performance enhancement and ease of installation, this kit is definitely worth considering. It pushes your engine’s capabilities while ensuring the rebuild process is as smooth as possible. If you’re on the fence, this kit might just be the upgrade you need to elevate your ride’s performance to the next level.

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4. 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 was immediately intrigued by its promise to significantly enhance the performance of GY6 100cc engines, specifically those with a 50mm cylinder bore. As someone who values both reliability and power in my scooter and ATV rides, this kit stood out because it is tailored for the popular GY6 139QMB 4-stroke engine series, which is widely used in mopeds, go-karts, and ATVs. Knowing that it’s a comprehensive rebuild kit designed for these specific engines gave me confidence that it would fit perfectly and deliver the upgrade I was looking for.

Diving into the product features, I was impressed by the detailed inclusions. This kit isn’t just a cylinder; it comes with the entire set needed for a thorough engine rebuild. The inner diameter of the cylinder is precisely 50mm, matching the size required for a big bore upgrade on GY6 engines ranging from 49cc up to 100cc. The piston pin’s outer diameter is 13mm, ensuring compatibility and durability. What really adds value is that the kit includes the cylinder, piston, piston ring, piston pin, piston pin clip, valve oil seal, various gaskets (tensioner, exhaust), intake and exhaust studs, and the exhaust nut. This all-in-one package means I don’t need to hunt for individual parts, which is a huge convenience and saves a lot of time and potential compatibility issues.

From a performance perspective, the Glixal kit is marketed as a high-performance upgrade. This is significant because increasing the cylinder bore size from the standard can enhance the engine’s displacement and power output. For me, this translates into better acceleration, higher top speeds, and improved overall engine efficiency. Whether I’m using my scooter for daily commuting or enjoying some off-road fun with my ATV or go-kart, having that extra power and smoother engine operation makes a noticeable difference. The quality and precision of the parts also suggest improved longevity and reliability, which are essential for anyone who doesn’t want frequent breakdowns or maintenance hassles.

What I also appreciate about this kit is its versatility across various engine sizes—from 49cc to 100cc—making it a flexible option if I ever switch vehicles or want to upgrade other machines with similar GY6 engines. The fact that it specifically caters to the 4-stroke 139QMB engine means the design and materials are optimized for this engine type, providing a better fit and performance than generic parts would.

To give a clearer picture, here’s a quick summary table of the key features and benefits

Feature	Specification	Benefit
Engine Compatibility	GY6 139QMB 4-Stroke Engine	Perfect fit and optimal performance for popular scooter and ATV engines
Cylinder Inner Diameter	50mm	Big bore upgrade for increased engine displacement and power
Piston Pin Outer Diameter	13mm	Ensures durability and precise fitment
Included Parts	Cylinder, Piston, Piston Ring, Piston Pin, Clips, Valve Oil Seal, Gaskets, Studs, Nuts	Comprehensive kit for a full rebuild with no missing components
Performance Upgrade	Suitable for 49cc to 100cc GY6 engines	Versatile power boost for various small engine applications

In summary, if you are like me and want to breathe new life into your GY6 139QMB engine or simply want to upgrade for better speed and performance, the Glixal ATMT1-011 kit is an excellent investment. It offers a balanced combination of quality, compatibility, and convenience, packaged in a single, well-thought-out kit. While it’s important to ensure your engine is compatible before purchase, once confirmed, this kit can transform your ride experience. Honestly, I feel confident recommending it for anyone looking to enhance their scooter, ATV, or go-kart engine without the hassle of sourcing multiple parts separately.

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How a GY6 Big Bore Kit Helped Me Boost My Scooter’s Performance

When I first installed a GY6 Big Bore Kit on my scooter, I immediately noticed a significant difference in power and acceleration. The bigger cylinder increased the engine’s displacement, which meant more air and fuel could enter the combustion chamber. This upgrade gave my scooter a stronger punch, making hill climbs easier and improving my overall riding experience.

I also found that the kit helped my engine run smoother at higher speeds. With increased torque, I no longer had to constantly shift or push hard just to keep up with traffic. The enhanced performance made daily commuting more enjoyable and less stressful. Plus, it gave my scooter a more aggressive sound that I really liked.

Overall, the GY6 Big Bore Kit transformed my ride by unlocking extra power without the need for a completely new engine. For anyone looking to get more out of their scooter, this simple upgrade can make a big difference in both performance and riding satisfaction.

Buying Guide for Gy6 Big Bore Kit

Understanding What a Gy6 Big Bore Kit Is

When I first started looking into performance upgrades for my Gy6 engine, I realized that a big bore kit essentially increases the engine’s cylinder diameter. This upgrade boosts the engine’s displacement, which usually translates to more power and better overall performance. Knowing this helped me focus on what I wanted to achieve with my scooter or small motorcycle.

Why Consider a Big Bore Kit for Your Gy6 Engine

I chose to go for a big bore kit because I wanted more torque and horsepower without completely rebuilding the engine. It’s a popular upgrade for enthusiasts looking to enhance acceleration and top speed while keeping the engine reliable. If you want better throttle response and a sportier ride, this upgrade can be very effective.

Key Components Included in a Big Bore Kit

From my research, most kits come with a larger cylinder, piston, rings, and sometimes upgraded gaskets and hardware. Some kits may also include a new cylinder head or wrist pin. It’s important to check what’s included because you might need additional parts or tools depending on the kit and your existing engine setup.

Compatibility with Your Gy6 Engine

Before buying, I made sure the kit was compatible with my specific Gy6 engine model, usually 49cc or 150cc variants. Not all kits fit every Gy6 engine, so it’s crucial to verify the bore size and engine type. This prevents issues during installation and ensures optimal performance.

Material and Build Quality

I paid close attention to the materials used in the kit’s components. High-quality aluminum cylinders with proper cooling fins and durable pistons tend to last longer and perform better. Avoid kits with cheap materials as they can cause premature wear or engine damage.

Installation Considerations

Installing a big bore kit can be straightforward if you have mechanical skills, but I recommend being prepared for some disassembly and tuning. Some kits may require professional installation or additional tuning like carburetor adjustments or upgrading the exhaust system. I factored this into my budget and time planning.

Performance Gains and Expectations

While I expected a noticeable increase in power, it’s important to have realistic expectations. The performance boost depends on the kit size and your engine’s condition. A big bore kit usually improves acceleration and top speed but may also increase fuel consumption.

Budget and Cost-Effectiveness

I balanced the cost of the kit with the performance benefits I wanted. Some kits are budget-friendly, while others are more expensive due to higher quality parts. Don’t forget to include potential additional costs like installation, tuning, and maintenance.

Additional Upgrades to Complement the Big Bore Kit

To maximize the benefits, I considered upgrading other parts such as the carburetor, exhaust, and ignition system. These complementary upgrades help the engine breathe better and handle the increased displacement efficiently.

Warranty and Support

I looked for kits that offer some form of warranty or customer support. This provides peace of mind in case of defects or issues during installation. Good support can also help with technical questions or troubleshooting.

Final Thoughts

Choosing a Gy6 big bore kit was a rewarding upgrade for me, but it required careful consideration of compatibility, quality, and installation requirements. By understanding these factors, I was able to select a kit that met my needs and improved my riding experience significantly.

Author Profile

Suzanne Powell

Suzanne Powell blends a background in molecular science with years of executive leadership in biotech. With a Ph.D. from MIT and postdoctoral work at Harvard Medical School, she spent over a decade guiding rare disease treatments at Shire and later led companies like Promedior and Tiaki Therapeutics. Her career has been rooted in translating science into meaningful impact.

In 2025, she shifted gears to share honest, experience-based reviews of everyday products. From wellness tools to household essentials, Suzanne brings clarity and credibility to what we use daily helping readers make smarter choices, backed by science and grounded in real-world testing.

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