CG 125cc Piston Assy Pin 13mm

CG125 Piston Assembly - 13mm Pin

🏍️ Piston Assembly · Piston Kit · Engine Rebuild Part · CG125 Specific

For CG125 Engines · Piston Diameter 56.5mm · 13mm Piston Pin · Affordable Replacement Choice

This is the CG125 Piston Assembly (13mm Pin) — an excellent inexpensive replacement piston kit. This kit includes the piston, compression rings, oil control ring, piston pin, and circlips, making it an ideal choice for engine overhaul or performance restoration.

The piston is a core moving component of the engine combustion chamber, directly withstanding high temperature and pressure from combustion and transmitting power to the crankshaft via the connecting rod. This piston assembly is manufactured from high-quality aluminum alloy with a piston diameter of 56.5mm and a piston pin diameter of 13mm, paired with high-precision piston rings to ensure excellent sealing and wear resistance, effectively reducing oil consumption and restoring engine power.

⚠️ 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 piston assembly is compatible with the following engines and vehicles:

• Engine Types: CG125 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, piston ring replacement, oil burning repair, power restoration

• High-Quality Aluminum Piston: Made from high-strength aluminum alloy with lightweight construction, high strength, low thermal expansion, and precise fit with cylinder walls.
• Precision-Machined Ring Grooves: Ring grooves are precision-machined to ensure smooth piston ring movement and excellent sealing performance.
• High-Quality Piston Ring Set: Piston rings are made from high-grade alloy cast iron with uniform tension and excellent wear resistance, including 2 compression rings and 1 oil ring.
• Precision Piston Pin: 13mm diameter piston pin is heat-treated and precision-ground for high strength and wear resistance.
• Included Circlips: Circlips are provided to securely retain the piston pin, preventing it from coming loose.
• Complete Kit: Includes piston, piston rings, piston pin, and circlips — everything needed for a professional rebuild.
• Excellent Value: High quality at an affordable price — the ideal choice for engine overhaul.

🔧 Installation Guide

1. Ensure the engine is completely cooled and clean carbon deposits from the ring grooves before installation.
2. When installing piston rings, note the orientation (markings facing up if present) and stagger ring gaps 120 degrees apart to prevent blow-by.
3. Apply a small amount of engine oil to the piston skirt and piston rings before installation to prevent dry start-up.
4. When installing the piston pin, ensure the circlips are fully seated in the circlip grooves and check they are secure.
5. When installing the piston, ensure the arrow or marking on the piston faces the exhaust side (or follow the original orientation).
6. Use a piston ring compressor tool to avoid damaging the cylinder wall during installation.
7. After installation, manually rotate the crankshaft to confirm smooth piston movement without binding.
8. It is recommended to inspect cylinder wear and replace the cylinder if necessary for optimal results.

Proper break-in is essential after installing a new piston 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 Piston Assembly with 56.5mm piston diameter and 13mm piston pin. Designed for CG125 series 125cc 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: Piston assembly installation involves critical engine components. Professional installation is strongly recommended. Pay attention to piston ring orientation and gap staggering during installation. Product images are for reference only; please refer to the actual product.