CG 125cc Cylinder Assy Pin 13mm

CG125 Cylinder Assembly - 13mm Pin

🔧 Cylinder Assembly · Cylinder Kit · Engine Rebuild Kit · CG125 Air Cooled Specific

For CG125 Air Cooled Engines · Includes Aluminum Cylinder, Piston, Piston Rings & Pin · 13mm Piston Pin

This is the CG125 Cylinder Assembly (13mm Pin) — a replacement cylinder kit for the CG125 air cooled engine. This kit includes the aluminum cylinder, piston, piston rings, and piston pin, making it an ideal choice for engine overhaul or performance restoration.

The cylinder assembly is a core component of the engine, providing a precision guide for piston reciprocating motion and forming a sealed combustion chamber with the piston. This kit features a high-quality aluminum cylinder with a cast iron liner for excellent wear resistance and heat transfer. The piston is manufactured from high-strength aluminum alloy with a piston diameter of 56.5mm and a piston pin diameter of 13mm. This is the perfect replacement when the original cylinder suffers from scoring, excessive wear, or when piston rings can no longer seal effectively.

⚠️ Important: Piston Pin Size Confirmation

This is the 13mm piston pin version. CG125 engines come with two common piston pin sizes: 13mm and 15mm. Please verify your original piston pin diameter before purchasing to ensure correct selection. If unsure, measure the original piston pin or consult your engine service manual.

This cylinder assembly is compatible with the following engines and vehicles:

• Engine Types: CG125 Air Cooled 4-stroke engines
• Piston Pin Size: 13mm (verify your original is 13mm)
• Vehicle Types: Honda CG125, Chinese-made CG series motorcycles, dirt bikes, street bikes
• Applications: Engine overhaul, cylinder scoring repair, oil burning repair, power restoration

• Complete Kit: Includes cylinder, piston, piston rings, piston pin, and circlips — everything needed for a professional rebuild.
• High-Quality Aluminum Cylinder: High-strength aluminum construction with cast iron liner for excellent heat dissipation and wear resistance.
• Precision Piston: 56.5mm diameter piston made from high-strength aluminum alloy with low thermal expansion for precise cylinder fit.
• High-Quality Piston Ring Set: Alloy cast iron rings with uniform tension and excellent sealing performance.
• Precision Piston Pin: 13mm diameter pin is heat-treated and precision-ground for high strength and wear resistance.
• OEM Specification Standards: Manufactured to CG125 original specifications for perfect fitment.

🔧 Installation Guide

1. Ensure the engine is completely cooled and disconnect the negative battery terminal before starting.
2. When removing the old cylinder, clean the crankcase mating surface thoroughly to remove old gasket residue.
3. When installing piston rings, pay attention to orientation and stagger ring gaps 120 degrees apart.
4. Apply a small amount of engine oil to the cylinder wall and piston rings before installation to prevent dry start-up.
5. Use a new cylinder head gasket to ensure proper sealing.
6. When installing the cylinder, use a piston ring compressor tool to avoid damaging the rings and cylinder wall.
7. Tighten cylinder head bolts in a diagonal pattern in multiple stages to the specified torque (approx. 20-25 N·m).
8. After installation, start the engine and check for gas or oil leaks; allow proper break-in period.

Proper break-in is essential after installing a new cylinder assembly to achieve optimal piston ring-to-cylinder wall seating:

• Break-In Period: Recommended 500-800 km (300-500 miles).
• RPM Control: Avoid prolonged high RPM operation during break-in; keep RPM below 70% of maximum.
• Load Control: Avoid hard acceleration, heavy loads, and steep hill climbing during break-in.
• Oil Change: Change oil after the first 200-300 km (120-180 miles), and again after the break-in period is complete.
• Oil Quality: Use high-quality mineral oil during break-in; switch to synthetic oil after break-in.

⚠️ Important Notice: This product is the CG125 Cylinder Assembly with 56.5mm bore diameter and 13mm piston pin. Designed for CG125 air cooled engines.
Spec Confirmation: Before purchasing, verify your original piston pin diameter is 13mm (not 15mm). CG125 engines have two piston pin sizes — please measure and confirm before ordering.
Installation Caution: Cylinder assembly installation involves critical engine components. Professional installation is strongly recommended. Always use a new cylinder head gasket and tighten bolts to the specified torque. Product images are for reference only; please refer to the actual product.