The Honda 13103-ZA8-000 Piston (0.50) is a genuine OEM oversize piston designed for a wide range of Honda engines and equipment, including BF2 and BF20 portable outboard motors, EM500, EM600, EM650, EX650, and EX800 generators, the F200 tiller, G100 horizontal shaft engines, HR17 lawn mowers, and WA15 and WB15 water pumps. As a genuine Honda part, it is manufactured to the same specifications as the original component and is the correct choice when rebuilding a worn bore that has been honed to the 0.50 mm oversize. Confirm fitment against your machine's serial number using the compatibility table, as Honda supersedes and revises parts across serial ranges. This piston is intended for a bore already machined to accept the 0.50 mm oversize — always verify the oversize designation matches your engine's current bore before ordering.
Key Features
- Genuine OEM Oversize Piston — manufactured by Honda to match the original piston geometry, ring land dimensions, and pin bore tolerances required for a proper rebuild at the 0.50 mm oversize specification.
- Correct Oversize Designation — the (0.50) designation identifies this as the 0.50 mm oversize variant; match this exactly to your machined bore before ordering, as multiple oversize options may be listed for these models.
- Broad Equipment Coverage — a single part number serves BF2 and BF20 portable outboard motors, EM500, EM600, EM650, EX650, and EX800 generators, the F200 tiller, G100 engines, HR17 lawn mowers, and WA15 and WB15 water pumps; check the fitment table to confirm your specific model and serial range.
- Serial Number Verification Recommended — Honda revises parts at production serial breaks; cross-reference your machine's serial number against the compatibility table to confirm part number 13103-ZA8-000 is correct for your unit.
- Restores Compression and Power — a correctly sized OEM piston seals the bore effectively after machining, restoring compression, combustion efficiency, and normal engine output in place of a worn or scored original.
The piston is the reciprocating component at the heart of the combustion cycle. It travels up and down within the cylinder bore, compressing the air-fuel mixture on the upstroke and transmitting the force of combustion to the crankshaft via the connecting rod on the power stroke. When a cylinder bore becomes worn, scored, or out of round, it is machined to a larger, precise diameter — an oversize — and a matching oversize piston is fitted to restore the correct running clearance. A worn or undersized piston allows combustion gases to bypass the rings, resulting in lost compression, increased oil consumption, hard starting, and reduced power output. Fitting a correctly sized genuine OEM piston after a bore recondition brings the engine back to proper operating condition.
Part Details
| Part Number | 13103-ZA8-000 |
|---|---|
| Brand | Honda |
| Part Type | Genuine OEM |
| Description | Piston (0.50) |
Compatibility & Fitment
| Name | Models | Serial Range |
|---|---|---|
| Generator | EM500, EM600, EM650, EX650, EX800 | All |
| Horizontal Shaft Engine | G100 | All |
| Lawn Mower | HR17 | All |
| Portable Outboard Motor | BF2, BF20 | All |
| Tiller | F200 | All |
| Water Pump | WA15, WB15 | 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.
