| Model | HJ100 |
| CYL DIA | 50 |
| TOTAL HIGH | 36.7 |
| COMP DIST | 20.2 |
| RING | 1.0*1.0*2.0 |
| PIN DIA | 13 |
| PIN LENGTH | 38 |

CYL DIA (Cylinder Diameter): 50 mm – This precision-machined diameter ensures a tight, leak-free fit within 100cc cylinder bores, critical for maintaining peak compression. The 50mm size optimizes combustion pressure, delivering responsive low-end torque ideal for navigating city traffic (on motorcycles) or hauling light cargo (on tricycles) while keeping fuel consumption economical.
TOTAL HIGH (Total Height): 36.7 mm – The compact total height is a defining advantage, designed to fit the HJ100’s streamlined engine bay. It saves vertical space without compromising structural integrity, ensuring seamless integration with existing motorcycle parts or tricycle parts and preserving the vehicle’s lightweight handling.
COMP DIST (Compression Distance): 20.2 mm – This carefully calculated distance optimizes the engine’s compression ratio, striking a balance between power output and fuel efficiency. It ensures efficient combustion in 100cc setups, preventing pressure loss and maximizing energy harnessed from each fuel-air mixture—key for cost-conscious daily use.
Piston Ring Dimensions: 1.01.02.0 mm – The (included) Piston ring set features three specialized rings (primary compression, secondary compression, oil control) with precise thicknesses. These rings work in tandem with the HJ100 Piston to seal the cylinder, prevent oil contamination of the combustion chamber, and enhance heat transfer—essential for 100cc engines operating in stop-and-go or prolonged-use scenarios.
PIN DIA (Piston Pin Diameter): 13 mm – The 13mm piston pin ensures a secure, low-friction connection to the connecting rod. Its robust diameter handles the stresses of 100cc combustion while maintaining smooth movement, extending the piston’s service life.
PIN LENGTH: 38 mm – This length provides stable support for the connecting rod, distributing pressure evenly across the piston’s wrist pin boss. It ensures alignment and reduces lateral movement, preventing premature wear on both the piston and rod components.
HJ100 Motorcycle Compatibility – It’s a direct replacement for all HJ100 variants, including base models and upgraded editions. Whether you’re repairing a well-used HJ100 that’s logged thousands of kilometers or restoring an older model, the HJ100 Piston integrates seamlessly with the bike’s original motorcycle parts to restore factory-level performance.
100cc Tricycle Compatibility – For 100cc utility tricycles used for small-scale cargo transport (e.g., urban food delivery, rural errand-running, or light farm work), the HJ100 Piston is a reliable upgrade. It works with standard tricycle engine setups, pairing with tricycle parts to deliver the durability needed for hauling 80+ kg loads without straining the engine.
100cc Small-Engine Compatibility – Beyond two and three-wheelers, the HJ100 Piston fits 100cc small-engine machinery (e.g., mini generators, small water pumps) that require 50mm piston dimensions, expanding its utility across engine parts applications.
HJ100-Specific Engineering – Unlike generic pistons designed for “one-size-fits-all” 100cc engines, it’s engineered exclusively to match the HJ100’s engine specifications. This ensures perfect fit, optimal compression, and performance that aligns with the vehicle’s original design.
Dual-Vehicle Versatility – It works seamlessly with both motorcycle parts and tricycle parts, making it a versatile solution for users who own multiple 100cc vehicles or small repair shops serving diverse clients.
Value for Money – The combination of premium materials, precision machining, and long-lasting durability delivers exceptional value. While cheaper pistons may save money upfront, they often fail within 6–12 months—whereas the HJ100 Piston provides reliable performance for 2–3 years, reducing long-term replacement costs.
Compliance with OEM Standards – The HJ100 Piston meets or exceeds original equipment manufacturer (OEM) standards for the HJ100, ensuring it’s a direct, safe replacement for factory parts.
| Model | HJ100 |
| CYL DIA | 50 |
| TOTAL HIGH | 36.7 |
| COMP DIST | 20.2 |
| RING | 1.0*1.0*2.0 |
| PIN DIA | 13 |
| PIN LENGTH | 38 |

CYL DIA (Cylinder Diameter): 50 mm – This precision-machined diameter ensures a tight, leak-free fit within 100cc cylinder bores, critical for maintaining peak compression. The 50mm size optimizes combustion pressure, delivering responsive low-end torque ideal for navigating city traffic (on motorcycles) or hauling light cargo (on tricycles) while keeping fuel consumption economical.
TOTAL HIGH (Total Height): 36.7 mm – The compact total height is a defining advantage, designed to fit the HJ100’s streamlined engine bay. It saves vertical space without compromising structural integrity, ensuring seamless integration with existing motorcycle parts or tricycle parts and preserving the vehicle’s lightweight handling.
COMP DIST (Compression Distance): 20.2 mm – This carefully calculated distance optimizes the engine’s compression ratio, striking a balance between power output and fuel efficiency. It ensures efficient combustion in 100cc setups, preventing pressure loss and maximizing energy harnessed from each fuel-air mixture—key for cost-conscious daily use.
Piston Ring Dimensions: 1.01.02.0 mm – The (included) Piston ring set features three specialized rings (primary compression, secondary compression, oil control) with precise thicknesses. These rings work in tandem with the HJ100 Piston to seal the cylinder, prevent oil contamination of the combustion chamber, and enhance heat transfer—essential for 100cc engines operating in stop-and-go or prolonged-use scenarios.
PIN DIA (Piston Pin Diameter): 13 mm – The 13mm piston pin ensures a secure, low-friction connection to the connecting rod. Its robust diameter handles the stresses of 100cc combustion while maintaining smooth movement, extending the piston’s service life.
PIN LENGTH: 38 mm – This length provides stable support for the connecting rod, distributing pressure evenly across the piston’s wrist pin boss. It ensures alignment and reduces lateral movement, preventing premature wear on both the piston and rod components.
HJ100 Motorcycle Compatibility – It’s a direct replacement for all HJ100 variants, including base models and upgraded editions. Whether you’re repairing a well-used HJ100 that’s logged thousands of kilometers or restoring an older model, the HJ100 Piston integrates seamlessly with the bike’s original motorcycle parts to restore factory-level performance.
100cc Tricycle Compatibility – For 100cc utility tricycles used for small-scale cargo transport (e.g., urban food delivery, rural errand-running, or light farm work), the HJ100 Piston is a reliable upgrade. It works with standard tricycle engine setups, pairing with tricycle parts to deliver the durability needed for hauling 80+ kg loads without straining the engine.
100cc Small-Engine Compatibility – Beyond two and three-wheelers, the HJ100 Piston fits 100cc small-engine machinery (e.g., mini generators, small water pumps) that require 50mm piston dimensions, expanding its utility across engine parts applications.
HJ100-Specific Engineering – Unlike generic pistons designed for “one-size-fits-all” 100cc engines, it’s engineered exclusively to match the HJ100’s engine specifications. This ensures perfect fit, optimal compression, and performance that aligns with the vehicle’s original design.
Dual-Vehicle Versatility – It works seamlessly with both motorcycle parts and tricycle parts, making it a versatile solution for users who own multiple 100cc vehicles or small repair shops serving diverse clients.
Value for Money – The combination of premium materials, precision machining, and long-lasting durability delivers exceptional value. While cheaper pistons may save money upfront, they often fail within 6–12 months—whereas the HJ100 Piston provides reliable performance for 2–3 years, reducing long-term replacement costs.
Compliance with OEM Standards – The HJ100 Piston meets or exceeds original equipment manufacturer (OEM) standards for the HJ100, ensuring it’s a direct, safe replacement for factory parts.