Best Bore Kit For 125Cc: Compare 10 Cylinder and Piston Kits

#1 · Best Overall

1. GOOFIT 52.4mm Cylinder Kit

• Package Dimensions: 5.71 x 5.51 x 4.65 in
• Weight: 6.82 lb

Best for: Lifan horizontal-engine rebuilds.

Why it ranks #1: Specifically lists Lifan 125cc LF125 horizontal engines, with a 52.4mm bore, 50mm bolt-hole spacing, 14mm piston pin, piston, and gaskets.

A 52.4mm bore with a specified 50mm bolt-hole spacing makes the GOOFIT kit a dimension-led choice for Lifan 125cc LF125 horizontal engines. Its listed piston pin measures 14mm, giving rebuilders several concrete measurements to compare with their existing dirt bike, pit bike, or ATV engine parts.

The iron cylinder block, forged piston, and stated resistance to high temperature and pressure address the demands described for sustained engine operation. A 14mm piston pin and flat-top piston are also specified, while the 50mm bolt-hole spacing and 52.4mm bore help buyers check core dimensions. Gaskets are included, and the kit is listed for Lifan LF125 horizontal engines, including dirt-bike and ATV applications; that engine-specific fitment limits its appeal outside the named family.

Skip it if you need a broad replacement for Chinese 90cc, 110cc, and 125cc engines; Anxingo’s 52.4mm kit lists that wider range.

This suits a Lifan LF125 horizontal-engine owner rebuilding a dirt bike, pit bike, or ATV and checking dimensions such as the 50mm bolt spacing and 14mm pin. Its named engine family is the key fit boundary for other 125cc platforms.

Listed on Amazon as: GOOFIT 52.4mm Engine Cylinder Big Bore with Piston Kit and Gaskets Replacement for Lifan 125cc LF125 Horizontal Engines Dirt Pit Bike ATV

#2 · Broadest Fitment

2. Anxingo 52.4mm Rebuild Kit

• Package Dimensions: 7.32 x 5.55 x 4.61 in
• Weight: 5.7 lb

Best for: Chinese 125cc engine rebuilds.

Why it ranks #2: Lists compatibility with most Chinese 90cc, 110cc, and 125cc engines and several named mini-bike brands; its cylinder design promotes heat dissipation.

A 52.4mm cylinder with a piston ring kit gives this Anxingo rebuild a defined bore size for many Chinese 90cc, 110cc, and 125cc engines. Its listed applications include ATVs, dirt bikes, pit bikes, go-karts, and pocket bikes, making it a broad option for owners working across small off-road machines.

The kit’s 52.4mm cylinder and piston ring set provide the core components for an engine rebuild, while the cylinder design is described as improving heat dissipation and reducing overheating risk. Listed replacement applications include SSR 110, BMS 110, Sunl 110, and Panda 100, alongside most Chinese 90cc to 125cc engines. That makes it useful for several small-vehicle categories, but buyers should compare their engine and model against the product’s compatibility details before starting the rebuild.

Skip it if you need a specifically listed Lifan LF125 horizontal-engine kit; the GOOFIT 52.4mm kit names that engine directly.

This suits owners rebuilding a listed Chinese small-engine ATV, dirt bike, pit bike, go-kart, or pocket bike who want a 52.4mm cylinder and rings. Check the engine’s exact model and configuration against the compatibility information before ordering.

Listed on Amazon as: Anxingo 52.4mm Engine Cylinder Big Bore Rebuild Kit, Cylinder with Piston Ring Kit for Most Chinese 90cc 110cc 125cc Engines, Replacement for Taotao, Replacement for SSR

#3 · Best GY6 Kit

3. Glixal 58.5mm GY6 Kit

• Package Dimensions: 5.8 x 5.2 x 4.6 in
• Weight: 2.86 lb

Best for: GY6 58.5mm rebuild bundle.

Why it ranks #3: Targets GY6 125cc–150cc 157QMJ engines with 54mm stud spacing and includes a piston, rings, pin, gaskets, and related hardware.

A 58.5mm sleeve and an extensive included-parts list make the Glixal kit a defined rebuild option for compatible GY6 125cc and 150cc engines. It names the 157QMJ engine and specifies 54mm stud spacing, helping buyers distinguish the intended installation from a similar GY6B layout.

The kit includes a cylinder, piston, rings, pin and clips, valve oil seal, several gaskets, intake and exhaust studs, and an exhaust nut. That component range can support a more complete rebuild workflow than sourcing each listed piece separately. Its 58.5mm sleeve and 54mm stud spacing narrow compatibility, however: the listing explicitly excludes GY6B engines with 57mm stud spacing. Check the engine family and stud layout before beginning installation.

Skip it if you have a GY6B engine with 57mm stud spacing; the SFNTXRT 61mm kit lists GY6 152QMI and 157QMJ engines instead.

This fits buyers rebuilding a GY6 125cc or 150cc engine that matches the listed 54mm stud spacing and wants the included piston, rings, gaskets, studs, and related parts. Avoid it for the explicitly excluded 57mm-stud GY6B configuration.

Listed on Amazon as: Glixal GY6 125cc 150cc to 155cc 58.5mm Racing Big Bore Cylinder Kit

#4 · Complete GY6 Rebuild

4. hauertzx 57.4mm GY6 Kit

• Package Dimensions: 11.42 x 7.09 x 6.69 in
• Weight: 8.8 lb

Best for: Broad GY6 vehicle applications.

Why it ranks #4: Lists 4-stroke GY6 125cc/150cc 157QMJ and 152QMI fitment and describes a complete cylinder rebuild kit for scooters, ATVs, and go-karts.

A 57.4mm bore and complete-cylinder-rebuild positioning give this hauertzx kit a clear role for 4-stroke GY6 125cc and 150cc engines. Its listed vehicle range spans Chinese scooters, ATVs, quads, and go-karts, offering a route for owners whose engine platform appears across several small-vehicle types.

The listing identifies 157QMJ and 152QMI engines and names a wide group of vehicle makes, including Roketa, Sunl, Taotao, SSR, and Zongshen. That breadth can help owners of Chinese scooters, quads, ATVs, or go-karts locate their vehicle family in the stated fitment. The 57.4mm bore provides a concrete specification to compare with the intended engine, while the supplied description does not enumerate the package contents in detail.

Skip it if you need a kit whose listing specifies a 54mm sleeve and detailed piston-and-gasket contents; the Glixal GY6 kit provides that inventory.

This is aimed at owners of listed GY6 125cc or 150cc Chinese scooters, ATVs, quads, and go-karts seeking a 57.4mm rebuild kit. Match the engine code and bore needs carefully, since the available listing gives limited package-content detail.

Listed on Amazon as: 57.4mm Big Bore Complete Cylinder Rebuild Kit Head Comp fit for 4 Stroke GY6 125cc 150cc 157QMJ 152QMI Engine Parts Chinese ATV Quad Scooter Go Kart

#5 · Horizontal Piston Set

5. RedCap 54mm Piston Set

• Package Dimensions: 5.2 x 4.85 x 2.05 in
• Weight: 6.5 oz

Best for: Horizontal 125cc piston refresh.

Why it ranks #5: Designed for 125cc horizontal-style dirt-bike engines and names SSR, Roketa, Taotao, Baja, and other brands; it supplies piston parts and head gaskets.

A piston-and-ring set with head gaskets, wrist pin, and washers makes the RedCap kit a focused parts choice for horizontal-style 125cc engines. Its listed compatibility includes SSR, Roketa, Taotao, Baja, BMS, and other named dirt-bike brands, giving owners a specific application list to check.

The package description identifies a piston kit with rings and head gaskets, while the title and listing also name a wrist pin and washers. That parts-focused selection suits a piston assembly refresh without presenting itself as a complete cylinder rebuild kit. Fitment is aimed at 125cc horizontal-style engines, with SSR, Roketa, Taotao, Baja, BMS, SUNL, JCL, Coolster, Jetmoto, and NST among the listed makes.

Skip it if you need a complete cylinder rebuild rather than piston parts; the Anxingo 52.4mm kit includes a cylinder and piston ring kit.

This suits owners refreshing the piston assembly on a listed 125cc horizontal-style pit bike or dirt bike, especially one from the named brands. It does not provide a complete cylinder rebuild, so account for that narrower parts scope.

Listed on Amazon as: RedCcap 54mm Bore Piston & Ring Set with Head Gaskets Kit for 125cc Pit Dirt Bike 125cc SSR Baja Roketa Apollo Bms Nst Taotao with the Horizontal Styled Engine ATV Dirt Bike Go Kart

#6

6. maXpeedingrods 54mm Kit

• Weight: 6.39 lb

Best for: Zongshen 1P54FMI rebuild.

Why it ranks #6: Its title specifies a 54mm bore rebuild kit for Zongshen 125cc, making the engine match relevant, although the supplied listing gives few component details.

The 1P54FMI engine designation is the key differentiator for this maXpeedingrods 54mm bore rebuild kit, which is listed for Zongshen 125cc. That specific engine naming gives owners a focused starting point for identifying a compatible cylinder rebuild, rather than relying on a broad 125cc label alone.

The product title identifies a 54mm bore and names the Zongshen 125cc 1P54FMI engine, providing two central details for an initial compatibility check. The available specifications list the manufacturer and product dimensions, but supply no component inventory or installation guidance. That makes the engine code and bore the most useful supplied facts for planning; confirm that the intended rebuild matches those identifiers using the product’s fuller listing information before disassembly.

Skip it if you need a kit with a listed piston, rings, and gaskets; the GOOFIT 52.4mm Lifan kit names those components.

This is for a Zongshen 125cc owner whose engine is identified as 1P54FMI and who is seeking a 54mm bore rebuild kit. The supplied information is limited, so use the engine designation and bore as fit boundaries.

Listed on Amazon as: maXpeedingrods 54mm Bore Cylinder Rebuild Kit 1P54FMI for Zongshen 125cc

#7

7. SFNTXRT 61mm GY6 Kit

• Package Dimensions: 10.24 x 7.17 x 6.77 in
• Weight: 5.94 lb

Best for: GY6 61mm complete component kit.

Why it ranks #7: Lists GY6 125cc/150cc 152QMI and 157QMJ fitment, a 61mm bore, 15mm piston pin, 69mm valve length, and cylinder head, camshaft, piston, and gaskets.

A CNC-machined 61mm cylinder paired with a head, camshaft, piston, and full gasket set makes the SFNTXRT kit a broad GY6 upgrade package. It lists 152QMI and 157QMJ engines and claims a zero-modification swap, giving owners a clear compatibility target and installation position to assess.

The kit combines the cylinder head, camshaft, piston, and full gasket set, consolidating several named parts for a GY6 rebuild workflow. Its 61mm bore, 15mm piston pin, and 69mm valve length provide concrete dimensions to compare with the engine. The listing names GY6 125cc and 150cc 152QMI/157QMJ applications and describes a seamless stock-parts swap, while noting a 0.5–1mm manual measurement variance that buyers should allow for when checking measurements.

Skip it if you need a GY6 61mm kit that explicitly warns crankcase boring is required; the hauertzx 61mm kit states that limitation.

This fits GY6 125cc or 150cc owners seeking a 61mm kit with a head, camshaft, piston, and gaskets for listed 152QMI or 157QMJ engines. Check the stated dimensions and measurement variance against the intended setup.

Listed on Amazon as: Big Bore Cylinder Kit 61mm for GY6 125cc

#8

8. hauertzx 61mm GY6 Kit

• Package Dimensions: 7.09 x 6.3 x 6.3 in
• Weight: 4.84 lb

Best for: GY6 61mm upgrade with valves.

Why it ranks #8: Lists GY6 125cc/150cc 152QMI and 157QMJ fitment, but its 63.8mm outer cylinder size may require crankcase boring on most bikes.

A 61mm cylinder and matching head with specified 26mm intake and 23mm exhaust valves give this hauertzx kit detailed GY6 upgrade dimensions. It names 152QMI and 157QMJ engines, but its 63.8mm outer cylinder size means many standard 125cc and 150cc installations need crankcase machining.

The kit specifies a 61mm bore and piston, a 15mm piston pin, and the two valve diameters, giving buyers several measurements for checking their engine setup. It is listed for GY6 150cc-to-180cc 4-stroke 152QMI and 157QMJ engines. The 63.8mm cylinder outer size is larger than the stated normal 61mm size, and the listing says most bikes require crankcase boring, so installation planning must include machine-shop work where needed.

Skip it if you want a 61mm GY6 cylinder kit advertised as needing no modifications; the SFNTXRT kit describes a seamless swap.

This is for GY6 owners who need the listed 61mm bore, valve dimensions, and 15mm piston pin for a 152QMI or 157QMJ setup. Account for the 63.8mm outer size and crankcase machining before choosing it.

Listed on Amazon as: 61mm Big Bore Cylinder Head Kit with Piston Ring Kits for GY6 125cc 150cc 152QMI 157QMJ Engine Scooter, ATV, Go Kart,Quad Moped

#9

9. LK LEAPING KNIGHT 61mm Kit

• Package Dimensions: 12.91 x 8.07 x 5.35 in
• Weight: 5.19 lb

Best for: Machine-shop GY6 61mm upgrade.

Why it ranks #9: Fits GY6 125cc/150cc engines and upgrades a 57.4mm bore to 61mm, but the listing says its 63.8mm outer cylinder requires crankcase machining on most bikes.

A 61mm bore upgrade with a 63.8mm cylinder outer size sets this LK LEAPING KNIGHT kit apart for GY6 125cc and 150cc owners prepared for machining. The listing says most installations require crankcase boring, making that workshop requirement essential to weigh before selecting this 180cc upgrade kit.

The bore increases from the stated standard 57.4mm to 61mm, while the 63.8mm outer size exceeds the listed normal 61mm cylinder outer size. The manufacturer notes that most bikes require crankcase boring and machine-shop work for installation. It names GY6 4-stroke 125cc and 150cc engines and 152QMI/157QMJ applications, so buyers can assess both engine family and machining needs before committing to the upgrade.

Skip it if you need a GY6 61mm kit advertised as a zero-modification swap; the SFNTXRT 61mm cylinder kit makes that claim.

Choose this for a GY6 125cc or 150cc owner pursuing the stated 180cc upgrade who can arrange crankcase boring. The 63.8mm outer size and machine-shop work are important installation boundaries, not minor details.

Listed on Amazon as: 61mm Big Bore Cylinder Head Kit for GY6 125cc/150cc Engine Upgrade to 180cc

#10

10. ZTDZZH 61mm Head Kit

• Package Dimensions: 7.95 x 6.26 x 6.14 in
• Weight: 5.04 lb

Best for: GY6 69mm-valve head upgrade.

Why it ranks #10: The listing describes a 61mm kit with 69mm valves for GY6 150cc–180cc engines, a less direct match for a stock 125cc engine than the other options.

A 61mm bore paired with 69mm valves defines this ZTDZZH cylinder head kit for GY6 engines. Its listing names 152QMI and 157QMJ engines and specifies a 125cc-to-180cc range, giving scooter, moped, and ATV owners clear dimensions to compare with their existing setup before choosing a head kit.

The 61mm bore and 69mm valve length are the key fit-related specifications, and the listing explicitly distinguishes these valves from 64mm valves. It identifies GY6 150cc-to-180cc 152QMI and 157QMJ engines, while the title also describes a 125cc-to-180cc application. Those details help narrow the intended engine family, but the listing supplies no included-component inventory beyond the cylinder head kit, so buyers should review the product images and description for the specific contents they need.

Skip it if you need an explicitly listed 58.5mm cylinder kit with piston and gaskets; Glixal’s GY6 125cc/150cc kit lists those components.

This is for GY6 owners comparing a 61mm bore and 69mm valve length for a scooter, moped, or ATV engine. Its stated engine range and dimensions are central fit considerations, so verify those details against the existing head before purchase.

Listed on Amazon as: 61mm Big Bore Cylinder Head Kit for GY6 125cc to 180cc Engine with 69mm Valves scooter taotao kazuma ATV Moped