The Honda 13103-ZF6-W01 Piston (0.50) is a genuine OEM oversize piston designed for the GX390 horizontal shaft engine and a wide range of Honda generators, including EB3800, EB4000, EB5000, EB6500, EB7000, EM3800, EM4000, EM5000, EM6500, EM7000, EU6500, and the GX390. This piston is the 0.50 mm oversize variant, intended for use after a cylinder bore has been machined to accept oversized dimensions — always confirm that your cylinder has been bored to the matching oversize specification before ordering. As a genuine Honda OEM component, it is manufactured to the exact tolerances required for proper ring seal, heat transfer, and long-term durability. Verify your unit's serial number against the fitment table to confirm this is the correct piston for your application.
Key Features
- Genuine OEM Oversize Piston — manufactured by Honda to exacting dimensional tolerances, ensuring proper bore clearance, ring groove geometry, and pin bore alignment for correct engine assembly
- 0.50 mm Oversize Variant — this piston is listed across multiple Honda units; the 0.50 oversize designation belongs to the part itself, so confirm your cylinder has been bored to the corresponding oversize before ordering
- Broad Generator and Engine Fitment — covers GX390 horizontal shaft engines and Honda EB, EM, and EU generator platforms, including both conventional and inverter generator models; check your serial number against the fitment table to confirm compatibility
- Restores Compression and Oil Control — a worn or scored piston allows combustion gases to bypass into the crankcase and oil to enter the combustion chamber, causing power loss, excessive oil consumption, and hard starting; this replacement piston restores proper cylinder sealing
The piston is the reciprocating component at the heart of the engine's power stroke. It travels up and down inside the cylinder bore, compressing the air-fuel mixture on the compression stroke and transmitting combustion force to the crankshaft via the connecting rod. The piston rings seal combustion gases above and control oil film below, so a piston that is worn, scored, or out of tolerance directly undermines compression, power output, and oil consumption. When a cylinder bore has been honed or machined oversize to clean up wear, a standard-dimension piston will not restore the correct running clearance — an oversize piston like this 0.50 mm variant is required to bring clearances back within specification and return the engine to full performance.
Part Details
| Part Number | 13103-ZF6-W01 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Piston (0.50) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Generator | EB3800, EB4000, EB5000, EB6500, EM3800, EM4000, EM5000, EM6500 | 4278970-9999999 |
| Horizontal Shaft Engine | GX390 | All |
| Inverter Generator | EB7000, EM7000, EU6500 | 4278970-9999999 |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
