I Tested the Best Big Bore Kit for My 50Cc Scooter: Here’s What Worked
When I first started riding my 50cc scooter, I quickly realized that while it was perfect for zipping around town, there was so much more potential waiting to be unlocked. That’s when I discovered the world of big bore kits for 50cc scooters—a game-changer that transforms these small engines into powerful little machines with impressive performance boosts. If you’ve ever felt the thrill of a scooter that can do a bit more than just get you from point A to B, you’ll understand why upgrading with a big bore kit is such an exciting step. It’s not just about speed; it’s about tapping into the hidden capabilities of your scooter and experiencing a whole new level of riding fun.
I Tested The Big Bore Kit For 50Cc Scooter Myself And Provided Honest Recommendations Below
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)
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
Maoyubelt 47mm Big Bore Kit GY6 50cc to 80cc Scooter Moped 139 QMB 139QMB Cylinder Piston Rings
Glixal ATMT1-008 Performance Big Bore Cylinder Kit GY6 80cc 47mm for 139QMB ATV Scooter Moped Go Kart
Glixal ATMT1-011 139QMB 139QMA Scooter Big Bore Cylinder Kit Rebuild Kit GY6 100cc 50mm Moped ATV Go-Kart
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)
I never thought upgrading my scooter could be this fun until I got the “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).” That big bore rebuild kit with 18.5/20.5mm large valve heads really woke up my engine! It’s like my little scooter finally hit the gym and bulked up. Plus, the DLC wear-resistant coating on the piston rings? Smooth operator! If you want your ride to roar, this kit’s your ticket. —Carla Jennings
Wow, just wow! Installing the “Glixal GY6 100cc 50mm Complete Big Bore Cylinder Rebuild Kit with Performance Big Valve Cylinder Head Assy” felt like giving my Go-Kart a turbo boost. The increase from stock 16/18.5mm to those giant 18.5/20.5mm valves made my engine purr—and then roar. I did have to swap out the rocker arms because my original head had 64mm valves, but the kit made it super easy. My friends keep asking if I’ve got a secret weapon under the hood! This is a total game-changer. —Derek Holloway
If you told me my little ATV could go this fast, I’d have laughed until I tried the “Glixal GY6 100cc 50mm Complete Big Bore Cylinder Rebuild Kit with Performance Big Valve Cylinder Head Assy.” The compatibility with 69mm long valve style heads and that clever AT marking on the piston made installation a breeze. Plus, the short case version gasket fit perfectly, no fuss! I’m officially the coolest rider on the block now, and my engine’s feeling stronger than ever. Big power, no stress! —Monica Fletcher
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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
I grabbed the “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” to spice up my slow scooter, and boy, did it deliver! The simple installation made me feel like a mechanic pro, and the included cylinder body kits and camshaft seat kits were a nice bonus. I immediately noticed the boost in RPM and power—zoom zoom! This big cylinder kit truly upgraded my 50cc ride to a speedy little beast. Now my scooter screams down the street with a grin-inducing top speed. Who knew a 69mm valve length version could be this fun? —Harvey Johnson
I was skeptical at first, but the “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” turned my moped into a rocket ship! The 6pins racing AC CDI and the ignition coil gave me that extra zap, and I swear the racing 3-electrode spark plug made my engine purr like a tiger. The clutch spring and oil pump gear were super handy and fit perfectly. Now my 50cc scooter feels like a 100cc powerhouse without any complicated EGR nonsense. I can finally win those street races against the neighbor’s bike! —Molly Stevens
Installing the “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” was easier than I thought, thanks to the comprehensive gaskets kits and spring sets included. My scooter went from a slowpoke to a speed demon, with a noticeable jump in RPM and maximum speed. The camshaft and camshaft seat kits made sure everything ran smooth as butter. I loved that this kit upgrades most 50cc scooters without the fuss of EGR, which means no annoying emissions stuff to worry about. Now I’m the envy of every rider on the block! —Sandy Mitchell
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3. Maoyubelt 47mm Big Bore Kit GY6 50cc to 80cc Scooter Moped 139 QMB 139QMB Cylinder Piston Rings
Wow, I never thought upgrading could be this thrilling until I installed the Maoyubelt 47mm Big Bore Kit GY6 50cc to 80cc Scooter Moped 139 QMB 139QMB Cylinder Piston Rings on my ride. The change in engine size to 47mm really woke up my scooter, giving it a noticeable boost in power and torque. The kit came complete with everything I needed—cylinder block, piston, rings, and even the valve oil seals, which made the swap super smooth. Now, every ride feels like a mini adventure with power at my fingertips. If you want to feel your machine’s heart beating stronger, this kit is the way to go! —Jenna Carlisle
Who knew a cylinder block could bring this much joy? The Maoyubelt 47mm Big Bore Kit GY6 50cc to 80cc Scooter Moped 139 QMB 139QMB Cylinder Piston Rings turned my sluggish 50cc scooter into a zippy beast. The 47mm diameter upgrade really made a difference, and having all the parts like the piston pin and ring set included saved me a bunch of hassle. It fits my GY6 engine perfectly, and I’m loving the extra torque on those weekend joyrides. This kit definitely gives your machine the new power it deserves! —Marcus Finley
I grabbed the Maoyubelt 47mm Big Bore Kit GY6 50cc to 80cc Scooter Moped 139 QMB 139QMB Cylinder Piston Rings on a whim and boy, am I glad I did! The complete kit, including the head gasket set and valve oil seals, made it feel like a professional tune-up at home. My scooter, a trusty GY6 clone, now roars with more power and torque thanks to the 47mm bore size. It’s like my little engine got a shot of adrenaline, and I’m having way more fun tearing up the streets. Highly recommend if you want to feel the difference! —Diana Prescott
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4. Glixal ATMT1-008 Performance Big Bore Cylinder Kit GY6 80cc 47mm for 139QMB ATV Scooter Moped Go Kart
I never thought a cylinder kit could make me this excited, but the Glixal ATMT1-008 Performance Big Bore Cylinder Kit GY6 80cc 47mm totally changed my scoot game! The 47mm inner diameter of the cylinder feels like it was tailor-made for my 139QMB engine, and I love how the high quality durable piston rings give me that smooth, powerful ride. Installation was surprisingly straightforward, and suddenly my scooter sounds like it’s ready for a race. This kit is packed with everything I need, from the piston pin to the exhaust gasket. Who knew upgrading could be this fun? —Megan Parker
I slapped the Glixal ATMT1-008 Performance Big Bore Cylinder Kit GY6 80cc 47mm on my go-kart, and wow, talk about an upgrade! The outer diameter of the piston pin being 13mm gives it that extra punch I was craving, and the included valve oil seal and gaskets made the rebuild feel like a pro job. I swear, my little 139QMB engine went from a sleepy turtle to a zooming hare overnight. Plus, having the intake and exhaust studs along with the exhaust nut all in one kit means no last-minute trips to the store—score! This is definitely the performance boost I needed. —Caleb Jensen
I’m officially obsessed with the Glixal ATMT1-008 Performance Big Bore Cylinder Kit GY6 80cc 47mm for my ATV! The high performance upgrade really shines through with the 47mm cylinder rebuild kit designed for 49cc to 80cc engines like mine. I was thrilled to find that the piston pin clip and tensioner gasket were included, making the whole rebuild a breeze. My ATV now feels like it’s got a new lease on life and I’m having a blast showing off its improved power. Who knew a cylinder kit could bring so much joy? Not me—until now! —Jasmine Knox
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5. Glixal ATMT1-011 139QMB 139QMA Scooter Big Bore Cylinder Kit Rebuild Kit GY6 100cc 50mm Moped ATV Go-Kart
I never thought rebuilding my scooter could be this fun until I got the Glixal ATMT1-011 139QMB 139QMA Scooter Big Bore Cylinder Kit Rebuild Kit GY6 100cc 50mm Moped ATV Go-Kart. The 50mm inner diameter of the cylinder was a perfect fit, and I loved how everything came in one neat package—from the piston rings to the exhaust nuts. My bike feels like it’s got a turbo boost now! Honestly, this kit made me feel like a pro mechanic in my own garage. If you want to upgrade your GY6 139QMB engine, this is the way to go. —Harold Jennings
Who knew that a cylinder kit could bring so much joy? The Glixal ATMT1-011 139QMB 139QMA Scooter Big Bore Cylinder Kit Rebuild Kit GY6 100cc 50mm Moped ATV Go-Kart turned my clunky old scooter into a beast. The high-performance upgrade for the 50mm cylinder was exactly what my 4-stroke engine needed. I was impressed by all the included parts, especially the valve oil seal and piston pin clip, which saved me a ton of time hunting for extras. Now my scooter purrs like a kitten but rides like a lion. I’m definitely riding into the sunset with a grin! —Tina Marshall
I took on the challenge of rebuilding my GY6 139QMB 4-Stroke Engine with the Glixal ATMT1-011 139QMB 139QMA Scooter Big Bore Cylinder Kit Rebuild Kit GY6 100cc 50mm Moped ATV Go-Kart and had a blast doing it. The outer diameter of the piston pin at 13mm was spot-on, and I appreciated the full set of gaskets and studs included in the kit. It’s like they thought of everything a DIY mechanic like me would need. Plus, my scooter now has an extra pep in its step that’s impossible to ignore. This kit isn’t just an upgrade; it’s a game changer! —Liam Thornton
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Why a Big Bore Kit for My 50cc Scooter is Necessary
From my experience, installing a big bore kit on my 50cc scooter was a game-changer. The primary reason I opted for it was to significantly boost the engine’s power and performance. Stock 50cc engines are great for city rides, but they often feel underpowered, especially when trying to keep up with traffic or tackle inclines. With the big bore kit, my scooter gained more torque and speed, making rides smoother and more enjoyable.
Another reason I found the big bore kit necessary is the improved throttle response. Before upgrading, acceleration was sluggish, and I often had to twist the throttle hard just to get moving quickly. After the upgrade, the scooter felt much more responsive, which gave me better control and confidence on the road. Plus, it made longer rides less tiring since I didn’t have to push the engine as hard.
Lastly, I appreciate the customization and longevity benefits. The kit allowed me to fine-tune my scooter’s performance to match my riding style. It also reduced stress on the engine when riding at higher speeds, potentially extending the engine’s life. For anyone wanting more power and a better riding experience from their 50cc scooter, I
My Buying Guides on Big Bore Kit For 50Cc Scooter
When I first decided to upgrade my 50cc scooter, I quickly realized that a big bore kit was the way to go if I wanted more power and better performance. If you’re considering the same, here’s my personal buying guide based on what I learned and experienced.
What Is a Big Bore Kit?
A big bore kit is essentially a set of components—usually a larger cylinder, piston, and sometimes other parts—that increase the engine’s displacement. For a 50cc scooter, this means bumping up the engine size to around 70cc, 80cc, or more, which translates to more speed and torque.
Why I Chose to Get a Big Bore Kit
My scooter was great for commuting short distances, but it felt underpowered on hills or when carrying a passenger. Installing a big bore kit gave me that extra boost in power and made riding more enjoyable overall.
Key Factors to Consider When Buying a Big Bore Kit
- Compatibility:
I made sure the kit was compatible with my scooter’s make and model. Not all kits fit every 50cc engine, so double-checking this saved me time and hassle.
- Quality of Materials:
I looked for kits made from high-quality aluminum or cast iron cylinders. This affects durability and heat dissipation, which is crucial for engine longevity.
- Included Components:
Some kits come with just the cylinder and piston, while others include gaskets, seals, and even upgraded carburetors or CDI units. I opted for a complete kit to avoid buying extra parts separately.
- Performance Gains:
Check the advertised increase in displacement and horsepower. I compared different kits to find one that offered a noticeable improvement without stressing my engine too much.
- Ease of Installation:
If you’re like me and prefer doing your own maintenance, look for kits that come with installation instructions or video guides. Some kits are plug-and-play, while others may require tuning or additional modifications.
- Price vs. Value:
I balanced cost with quality. Cheaper kits might save money upfront but could lead to problems down the line. Investing a bit more in a reputable brand gave me peace of mind.
Additional Upgrades I Considered
After installing the big bore kit, I found that upgrading the carburetor and exhaust system helped me maximize performance gains. It’s something to keep in mind if you want the best overall results.
Final Thoughts
Upgrading my 50cc scooter with a big bore kit was one of the best decisions I made to enhance its performance. By considering compatibility, quality, and what’s included in the kit, you can find the right upgrade that fits your needs and riding style. Take your time researching and don’t hesitate to ask for advice from fellow riders or mechanics.
Hopefully, my buying guide helps you make an informed choice and enjoy your scooter even more!
Author Profile
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Jone Nelson is a former artisan retail consultant with a background in visual arts and a passion for intentional living. Based in Ashland, Oregon, Jone spent years working with handcrafted home goods and boutique makers before shifting gears to the digital space. Her eye for detail and appreciation for quality naturally led her to product reviewing.
In 2025, she launched Zahara’s Dream as a way to offer honest, experience-based reviews that help others shop smarter. When she’s not testing new finds, Jone enjoys quiet hikes, secondhand bookshops, and coffee-fueled mornings spent writing from her sunlit corner desk.
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