# 1SL-12121-00 Yamaha Exhaust Valve | Genuine OEM Yamaha Outboard Part

🔧 Product Description

  

Genuine Yamaha Exhaust Valve - Part Number: 1SL-12121-00-00

  

A genuine Yamaha exhaust valve used in Yamaha four-stroke cylinder head valve train assemblies where OEM part number 1SL-12121-00-00 is specified. This valve controls exhaust gas flow from the combustion chamber and is a critical sealing component for compression, combustion efficiency and engine performance.

  

⚙️ Key Features

  

• Genuine Yamaha OEM exhaust valve

• Correct Yamaha part number 1SL-12121-00-00

• Exhaust-side cylinder head valve component

• Designed for Yamaha four-stroke engine valve train assemblies

• Precision valve face and stem design for correct sealing and heat transfer

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 1SL-12121-00-00 Yamaha exhaust valve reference

• 1SL-12121-00 short Yamaha exhaust valve format

  

OEM / Related Numbers:

  

• 1SL-12121-00-00

• 1SL-12121-00

• 1SL121210000

• 1SL1212100

  

Aftermarket / Verified Equivalents:

  

• ProX: 28.2444-1

• ProX titanium exhaust valve replacement family

• Aftermarket reference: 1SL-12121-00

• Aftermarket reference: 1SL1212100

• Yamaha 450 four-stroke exhaust valve replacement family where this OEM number is specified

  

🚤 Compatibility

  

Commonly used on:

  

• Yamaha four-stroke cylinder head valve train assemblies

• Yamaha exhaust valve applications where 1SL-12121-00-00 is specified by the parts diagram

  

Typically suits:

  

• Engine models:

• Yamaha YZ450F four-stroke valve applications where 1SL-12121-00-00 is specified

• Yamaha WR450F four-stroke valve applications where 1SL-12121-00-00 is specified

• Yamaha 450cc four-stroke cylinder head assemblies using the 1SL exhaust valve family

• Yamaha engine applications requiring OEM exhaust valve 1SL-12121-00-00

  

• Engine Type: Yamaha four-stroke engine

• Valve Type: Exhaust valve

• Year Range: model-specific Yamaha 1SL-series valve applications

• Fitment Note: Match by OEM part number and engine parts diagram before installation

  

🔌 Function

  

The exhaust valve opens during the exhaust stroke to allow burnt gases to exit the combustion chamber, then closes to seal the cylinder during compression and combustion.

  

Common signs of failure:

  

• Low compression

• Hard starting

• Poor idle quality

• Misfire or loss of power

• Excessive exhaust leakage

• Burnt, pitted or warped valve face

• Valve clearance repeatedly going out of specification

  

📦 Condition

  

• Genuine Yamaha part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 222.01 AUD
- **Vendor:** Yamaha
- **Tags:** Yamaha Marine Parts | Outboard Engine Parts & Components

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 222.01 AUD | In stock |

## Images

- 1SL-12121-00 Yamaha Exhaust Valve | Genuine OEM Yamaha Outboard Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/1sl-12121-00-exhaust-valve)
> Updated: 2026-07-11