Best Bore Kit For 125Cc: Match the Kit to Your Engine

#1 · Best Overall

1. Anxingo Lifan 125cc Kit

• Weight: 3.38 lb
• Package Dimensions: 8.5 x 6.34 x 4.49 in

Best for: Lifan 125cc horizontal-engine kit.

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

A 52.4mm aluminum cylinder with a 14mm piston pin gives this Anxingo kit a specific fitment profile for Lifan 125cc LF125 horizontal engines. The package also lists a piston kit and gaskets, making it relevant to top-end replacement work on compatible Chinese motorcycles, ATVs, go-karts, and dirt bikes.

The aluminum cylinder is presented for durability in high-stress engine conditions, while its 52.4mm bore defines the size to compare with the existing engine. A 14mm piston pin and flat-top piston design further narrow the required match, helping buyers assess component compatibility before starting work. Listed applications include Apollo and CRF alongside Lifan 125cc horizontal engines, across motorcycles, ATVs, go-karts, and dirt bikes.

Skip it if you have an Apollo RFZ125 engine; GOOFIT’s listing also excludes that engine, so select a kit matching your verified engine instead.

This suits Lifan LF125 horizontal-engine owners seeking a 52.4mm cylinder, piston kit, and gaskets for a listed motorcycle, ATV, go-kart, or dirt bike. The 14mm pin and RFZ125 exclusion are important fit boundaries.

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

#2 · Best Iron Cylinder

2. GOOFIT Lifan 125cc Kit

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

Best for: Lifan LF125 iron-cylinder rebuild.

Why it ranks #2: Targets Lifan 125cc LF125 horizontal engines and specifies an iron cylinder, 52.4mm bore, 14mm pin, piston, and gaskets.

A 52.4mm iron cylinder, 14mm piston pin, and flat-top piston define this GOOFIT kit for Lifan 125cc LF125 horizontal engines. The listing pairs those dimensions with a piston kit and gaskets, offering a focused top-end replacement option for compatible dirt bikes, pit bikes, and ATVs.

The specified 50mm bolt-hole spacing and 52.4mm bore provide concrete measurements for checking the engine before installation, while the 14mm pin and flat-top piston further define the required match. GOOFIT describes the cylinder as iron and the piston as precision forged, with high-temperature and high-pressure resistance claimed in the listing. It explicitly excludes Apollo RFZ125 engines, so the LF125 engine designation matters more than displacement alone.

Skip it if you need a 110cc Chinese model-specific kit; WOOSTAR’s listing names multiple 110cc applications and supplies valve dimensions.

Choose this for a Lifan LF125 horizontal-engine rebuild where the 52.4mm bore, 50mm bolt spacing, and 14mm pin match. It includes piston and gasket components, but the Apollo RFZ125 is explicitly excluded.

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

#3 · Zongshen Specific

3. maXpeedingrods Zongshen Kit

• Weight: 6.39 lb

Best for: Zongshen 125cc rebuild.

Why it ranks #3: Names the Zongshen 125cc 1P54FMI engine and a 54mm bore, making its stated application more focused than broad 110cc fitments.

The 54mm bore is the central specification of this maXpeedingrods cylinder rebuild kit, which is identified for the 1P54FMI engine in a Zongshen 125cc application. That specific engine designation gives buyers a clearer starting point for matching a rebuild part than a broad displacement label alone.

This listing identifies a 54mm bore and names both the 1P54FMI engine code and Zongshen 125cc application. Those details help frame a parts lookup around the engine designation and bore rather than assuming every 125cc engine shares the same dimensions. The product is described as a cylinder rebuild kit, but the supplied information does not detail individual kit components, so buyers should use the named engine and bore to assess whether it suits their planned service.

Skip it if you want a kit with piston, rings, and gaskets explicitly listed; GOOFIT’s Lifan 125cc kit names those components.

Consider this for a Zongshen 125cc rebuild when the engine is identified as 1P54FMI and the 54mm bore matches the job. The listing gives limited component detail, so it is not the clearest choice if you need a specified parts inventory.

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

#4 · GY6 Rebuild Kit

4. hauertzx GY6 57.4mm Kit

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

Best for: Broad GY6 vehicle coverage.

Why it ranks #4: Fits 4-stroke GY6 125cc and 150cc 157QMJ/152QMI engines and includes a complete cylinder rebuild kit.

A 57.4mm bore and complete cylinder rebuild format make this hauertzx kit a standard-size option for listed GY6 125cc/150cc four-stroke engines. Its compatibility reaches across Chinese scooters, ATVs, quads, and go-karts, with a notably long roster of named vehicle makes to help narrow the fitment check.

The 57.4mm bore is specified for GY6 125cc/150cc engines identified as 157QMJ and 152QMI, giving buyers concrete engine codes to compare before a rebuild. Its complete cylinder rebuild-kit description suits an engine service involving the top end, while the broad vehicle list includes makes such as Roketa, Taotao, Baja, Redcat, and SSR. Confirm the actual engine code, since vehicle brand alone does not establish fit.

Skip it if you need a listed parts breakdown before buying; WOOSTAR’s 52.4mm listing specifies cylinder, head, valves, and piston-ring kit.

This suits GY6 owners who can identify a 157QMJ or 152QMI engine and want a 57.4mm rebuild kit for a scooter, ATV, quad, or go-kart. Verify the engine code rather than relying on vehicle make alone.

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 · Largest Bore

5. TRKIMAL GY6 61mm Kit

• Weight: 5.02 lb
• Package Dimensions: 7.4 x 6.34 x 6.34 in

Best for: GY6 180cc machining project.

Why it ranks #5: Offers a 61mm GY6 bore upgrade for 125cc/150cc 152QMI and 157QMJ engines, but its 63.8mm exterior may require case boring.

A 61mm bore and stated upgrade to 180cc position this TRKIMAL kit for GY6 125cc/150cc owners planning a substantial engine modification. Its 63.8mm outer cylinder dimension is a key practical distinction: most bikes require crankcase boring, so installation involves machining rather than a simple standard-cylinder replacement.

The kit is described for 152QMI and 157QMJ GY6 engines and includes a cylinder head, valves, piston, and rings, bringing several top-end components into one rebuild package. Its 61mm bore supports the advertised 180cc upgrade, but the 63.8mm exterior exceeds the stated 61mm normal cylinder exterior for GY6 125/150 engines. On most bikes, crankcase boring is needed, which affects both installation planning and compatibility.

Skip it if you need a 52.4mm horizontal 110cc top end; ABCERRSI’s kit lists that engine type and bore dimensions.

This is for GY6 152QMI/157QMJ owners pursuing the stated 180cc conversion with access to crankcase machining. Check the 63.8mm exterior against the installation plan; it is not presented as a direct-fit standard cylinder.

Listed on Amazon as: GY6 125cc/150cc Engine Upgrade to 180cc with Cylinder Head Valves and Rebuilt Kit, 61mm Big Bore kits with Piston and Ring Assy for 152QMI 157QMJ Engine Chinese Scooter Moped ATV Go Kart Quad

#6

6. LK LEAPING KNIGHT GY6 Kit

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

Best for: GY6 case-machining upgrade.

Why it ranks #6: Specifies a 61mm bore upgrade for GY6 125cc/150cc engines and notes crankcase boring is needed on most bikes.

Its 61mm bore is presented as an upgrade from the GY6 57.4mm size, with a stated 180cc target for compatible 125cc/150cc engines. The key installation consideration is equally concrete: the 63.8mm cylinder exterior requires crankcase boring on most bikes, making machine-shop work part of the plan.

This cylinder-head kit is listed for GY6 four-stroke 125cc/150cc engines, including 152QMI and 157QMJ applications, and is described for Chinese scooters, ATVs, and go-karts. The bore increase from 57.4mm to 61mm supports the stated upgrade to 180cc, while the 63.8mm outer diameter affects installation: most bikes need crankcase boring. That makes this a better fit for a planned machining project than a drop-in replacement.

Skip it if you need a GY6 rebuild without crankcase machining; hauertzx’s 57.4mm kit matches the listed standard GY6 bore.

Choose it for a GY6 125cc/150cc owner pursuing the stated 180cc upgrade who can arrange crankcase boring. Its 63.8mm exterior is the critical fit boundary, so this is not a straightforward standard-size swap.

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

#7

7. Anxingo 52.4mm Rebuild Kit

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

Best for: Chinese 110cc replacement rebuild.

Why it ranks #7: Lists compatibility with most Chinese 90cc, 110cc, and 125cc engines, though its broad fitment requires careful model verification.

A 52.4mm bore paired with a cylinder and piston-ring kit gives this Anxingo set a defined role in rebuilding many Chinese 90cc, 110cc, and 125cc engines. Its listed applications span ATVs, dirt bikes, pit bikes, go-karts, and pocket bikes, while the cylinder design promotes heat dissipation.

The cylinder’s cooling-focused design is intended to move heat away more effectively, addressing overheating risk during engine operation. Including the piston and rings alongside the cylinder also brings core rebuild components together, which can simplify sourcing for a maintenance job. The fitment list names SSR, BMS, Sunl, Panda, Coyote, and Redcat models in addition to broader Chinese-engine applications; check engine details against the listed fitment before choosing it.

Skip it if you need a specifically identified GY6 125cc/150cc kit; hauertzx’s 57.4mm GY6 set names those engine families.

For owners rebuilding a listed Chinese 90cc–125cc ATV, pit bike, dirt bike, go-kart, or pocket bike, this combines the cylinder and piston-ring components. Match the engine and model carefully, since fitment is not universal.

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

#8

8. ATRACYPART 52.4mm Kit

• Weight: 5.4 lb
• Package Dimensions: 6.69 x 5.91 x 5.51 in

Best for: 110cc rebuild with fitment caveat.

Why it ranks #8: Lists select Chinese 110cc engines and potential compatibility with some 110cc–125cc applications, while warning against Apollo RFZ125 fitment.

This ATRACYPART kit combines a 52.4mm cylinder with a piston, rings, gaskets, and related rebuild components for select Chinese 4-stroke engines. Its broad 110cc model list includes Taotao, SSR, Kazuma, and Coolster, while the explicit Apollo RFZ125 exclusion makes engine identification especially important.

The 52.4mm specification and included cylinder block, piston, rings, and gaskets bring core parts together for maintenance or rebuilding of a compatible engine. Listed uses cover ATVs, dirt bikes, pit bikes, and go-karts, with multiple Chinese 110cc model names to guide the fitment check. The description specifically says it is not compatible with the Apollo RFZ125, so verify the engine identity instead of relying on a 125cc label.

Skip it if you need a kit for a Lifan LF125 horizontal engine; GOOFIT’s 52.4mm listing names that application.

This fits buyers rebuilding a listed Chinese 110cc four-stroke engine and wanting the cylinder, piston, rings, and gaskets together. The Apollo RFZ125 exclusion is a firm boundary; confirm the engine model before selecting it.

Listed on Amazon as: 52.4mm Engine Cylinder Big Bore Rebuild Kit for 110cc-125cc 4-Stroke Engine

#9

9. WOOSTAR 52.4mm Kit

• Weight: 9.79 lb
• Package Dimensions: 8.66 x 6.22 x 5.79 in

Best for: 110cc valve-and-head assembly.

Why it ranks #9: Its 52.4mm cylinder and head assembly fits listed 110cc engines, but the listing explicitly excludes 125 ZHEJIANG KANGDI.

A complete cylinder-and-head assembly with 66mm valves distinguishes this WOOSTAR kit from cylinder-only listings for four-stroke 110cc Chinese engines. Its 52.4mm cylinder, specified mounting dimensions, and named Taotao, SSR, and Coolster applications give buyers practical measurements and model references for a top-end replacement.

The listing provides a 52.4mm cylinder diameter, 49mm mounting-hole distance, and valve diameters of 23mm intake and 20mm exhaust, helping buyers compare key dimensions before installation. A cylinder, head, valve assembly, and piston-ring kit gather major top-end parts in one package. It names several 110cc models, but explicitly excludes 125 Zhejiang and Kangdi applications, making that boundary important when checking fit.

Skip it if you have a Lifan 125cc LF125 horizontal engine; Anxingo’s 52.4mm kit specifically lists that application.

For a compatible four-stroke 110cc owner needing a head, valves, cylinder, and piston-ring kit, its dimensions support a careful parts match. Avoid it for 125 Zhejiang or Kangdi engines, which the listing excludes.

Listed on Amazon as: WOOSTAR 52.4mm Big Bore Cylinder and Head 66mm Valves Assembly with Piston Ring Kit Replacement for 4 Stroke 110cc Chinese Taotao Coolster Engine ATV Go Kart Dirt Bike

#10

10. ABCERRSI 52.4mm Kit

• Weight: 10.41 lb
• Package Dimensions: 10.98 x 5.83 x 5.12 in

Best for: Measured 110cc horizontal-engine rebuild.

Why it ranks #10: Designed for horizontal 110cc Chinese engines, with 52.4mm bore and stated dimensions; it is a weaker match for a 125cc search.

Detailed dimensions—including a 52.4mm bore, 37mm piston height, and 48mm-by-50mm bolt spacing—make this ABCERRSI kit useful for a measured 110cc horizontal-engine rebuild. It is listed for Chinese Taotao and Coolster applications, among others, and includes the cylinder, head, piston-ring set, and gaskets.

The published bore, piston diameter, pin dimensions, and bolt-hole spacing give a mechanic concrete measurements to compare during parts selection, while the 45mm inlet and outlet hole distances add further installation checks. The listed compatibility includes Taotao 110, Coolster 110, SSR 110, and other Chinese horizontal 110cc engines. Cylinder, head, piston-ring components, and gaskets are included, consolidating key top-end service parts in one kit.

Skip it if you need a Lifan 125cc horizontal-engine kit; GOOFIT’s 52.4mm set specifically names LF125 applications.

A practical choice for owners servicing a listed Chinese horizontal 110cc engine who can compare the supplied dimensions during installation. Its stated applications center on 110cc models, so it is not the pick for a general 125cc rebuild.

Listed on Amazon as: 52.4mm Big Bore Cylinder and Head with Piston Ring Rebuild Kit and Gaskets Compatible with 4 Stroke Horizontal 110cc Chinese Taotao Coolster Engine ATV Go Kart Dirt Bike