The Honda 12000-Z5T-Q40 Cylinder Assembly is a genuine OEM component built for the GX390 horizontal shaft engine. As a factory-original part, this assembly is manufactured to the exact specifications Honda engineers designed for the GX390, ensuring a correct, direct-fit replacement when the original cylinder has suffered damage, excessive wear, or a bore that can no longer be salvaged by oversize pistons. Buyers should confirm their engine's serial number against the fitment table before ordering, as Honda supersedes cylinder components at production breaks.
Key Features
- Genuine OEM Cylinder Assembly — sourced directly from Honda, this assembly matches the original casting geometry, bore dimensions, and port configuration of the GX390, so no rework or adaptation is needed to accept the original piston, rings, and head.
- Complete Cylinder Assembly — supplied as a full assembly rather than a bare casting, reducing the number of individual components a technician must source and fit when rebuilding a seized or cracked GX390 short block.
- Critical to Compression and Cooling — the cylinder is the structural core of the engine: it houses the piston bore, forms the combustion chamber walls, and carries the cooling fins that dissipate heat. A cracked, scored, or worn-beyond-spec cylinder causes compression loss, overheating, and oil consumption that cannot be corrected by any other service item.
- Serial Number Verification Recommended — Honda revises cylinder assemblies across GX390 production runs; check your engine's serial number against the compatibility table to confirm this is the correct casting for your unit.
The cylinder assembly is the main structural housing of a four-stroke engine. On the GX390 horizontal shaft engine, it contains the precisely bored cylinder wall that guides the piston through its intake, compression, power, and exhaust strokes, and its external cooling fins draw heat away from the combustion zone during operation. When a cylinder develops a cracked casting, a scored or out-of-round bore, or damage beyond what honing and an oversize piston can correct, replacing the entire assembly restores the correct bore geometry and sealing surface that compression, oil control, and long-term engine health all depend on.
Part Details
| Part Number | 12000-Z5T-Q40 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Cylinder Assembly |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Horizontal Shaft Engine | GX390 | All |
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.
