The Honda 13102-812-000 Piston (0.25) is a genuine OEM oversize piston designed for E300, EM400, and ER400 generators. As a factory-sourced component, this piston is manufactured to Honda's exact dimensional tolerances for the 0.25 mm oversize bore specification — the critical measurement a machinist works to when reconditioning a worn cylinder. This part is listed for the E300, EM400, and ER400 generators; confirm that the 0.25 oversize designation matches your own engine's rebored cylinder before ordering.
Key Features
- Genuine OEM Sizing Accuracy — an oversize piston lives or dies by its dimensional precision; this Honda-sourced component carries the exact 0.25 mm oversize specification needed to achieve correct running clearance in a rebored cylinder.
- OEM Part for Generator Engine Rebuilds — sourced directly from Honda, this piston is built to the same specification as the original, supporting a full engine recondition rather than a stopgap repair.
- Oversize Variant — Verify Before Ordering — this is the 0.25 oversize version; it is intended for cylinders that have been bored to the corresponding oversize. Confirm your cylinder's rebore dimension matches the (0.25) specification before purchasing.
- Check Your Serial Number — Honda updates and supersedes parts at production breaks, so cross-reference the serial number on your generator against the fitment table to confirm this is the correct piston for your unit.
A piston is the reciprocating heart of the engine's power stroke — it compresses the air-fuel mixture, receives the force of combustion, and transfers that energy through the connecting rod to the crankshaft. An oversize piston is used specifically after cylinder boring: when a cylinder wall becomes worn or scored beyond the standard service limit, a machinist bores it to a precise oversize diameter, and a matching oversize piston restores the correct clearance between piston and bore. Without that tight, controlled fit, combustion gases blow past the rings, oil consumption rises, compression drops, and the generator loses the ability to produce steady power output. Using the correct oversize variant — here, the 0.25 mm oversize — is essential to a successful rebuild.
Part Details
| Part Number | 13102-812-000 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Piston (0.25) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Generator | E300, EM400, ER400 | 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.
