Description

The Sea-Doo 300 Piston/Ring Kit – +0.50 mm Oversize is a high-precision engine rebuild part, designed for cylinders that have undergone a second boring after advanced wear. It replaces OEM references 420892738 and 420916472 and is compatible with all Sea-Doo models equipped with the 1630 cc 300 hp engine produced between 2016 and 2024: GTX, RXP-X, RXT-X, GTR, and Explorer.

This +0.50 mm oversize kit is used when the cylinder has already been bored once to +0.25 mm and again shows wear requiring a second boring. It guarantees a perfect fit and optimal sealing to restore the original 300 hp.

Technical Specifications

Replaced OEM References: 420892738, 420916472
Associated References: 42091647, 420245436
Oversize: +0.50 mm (for cylinder rebored to 2nd oversize)
Engine Application: Sea-Doo 300 hp (1630 cc)
Contents: Complete piston + ring kit (as illustrated)
Condition: New
Type: Aftermarket SBT – OEM replacement
Weight: 0.715 kg
Regulated Substances: None
Installation: Restricted to qualified technician (prior boring required)

Compatibility

Compatible with Sea-Doo models equipped with the 300 hp (1630 cc) engine that have undergone a +0.50 mm oversize bore:

GTX 300 / GTX LTD 300 – 2016 to 2024
RXP-X 300 / RXP-X XRS 300 – 2016 to 2022
RXT-X 300 / RXT XRS 300 – 2016 to 2022
RXP 300 – 2018 to 2022
RXT 300 – 2019 to 2020
GTR 300 – 2024
Explorer 300 – 2024

⚠️ This kit is exclusively for cylinders rebored to +0.50 mm oversize. It is imperative to check your cylinder's bore size before ordering. Installation on a non-rebored cylinder or one with a different size would lead to immediate engine failure.

Why Choose +0.50 mm Oversize?

The +0.50 mm oversize is the second repair size available for the Sea-Doo 300 engine. It is used when the cylinder has already been bored once to +0.25 mm and again shows signs of wear. Typical situations justifying this choice are:

Cylinder already rebored to +0.25 mm with recurring wear
Deep scratches requiring a larger bore
Out-of-roundness or taper exceeding +0.25 mm tolerances

Choosing the correct repair size is essential to ensure the lifespan of the rebuilt engine. If in doubt, have your cylinder measured by an engine builder before ordering.