What does '0.040 inch undersize' mean for this piston?

This piston is designed for a cylinder bore that has been machined to be 0.040 inches larger than its original factory size. This is common during engine rebuilds to ensure a clean, perfectly round bore for optimal piston fit and sealing.

Is this piston a direct replacement for a stock Honda CBR 250R?

This piston is designed to fit the Honda CBR 250R, but it is 0.040 inch undersize. This means the cylinder will need to be bored to this specific size to ensure a proper fit. It is not a direct drop-in for an untouched stock bore.

What is the advantage of a forged piston over a cast piston?

Forged pistons are made by shaping aluminum under extreme pressure, which creates a denser, stronger grain structure. This makes them more resistant to deformation and failure under high heat and stress compared to cast pistons, making them ideal for performance applications or engine rebuilds.

JE Pistons 308446S Forged Piston - Honda CBR 250R

Name: JE Pistons Honda CBR 250R Piston Single
Brand: JE Pistons
SKU: je-pistons-je-pistons-honda-cbr-250r-piston-single-t14-695554
Price: 364.99 USD
Availability: BackOrder

JE Pistons Honda CBR 250R Piston Single

$364.99

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

JE Pistons 308446S forged piston for Honda CBR 250R. Single piston, 0.040 inch undersize.

Key Features

This is a 0.040 inch undersize piston.
Forged from a strong aluminum alloy for improved durability.
Designed as a single replacement piston for the Honda CBR 250R.
JE Pistons is a popular brand for performance engine components.
This piston fits right into the engine with proper cylinder machining.

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Product Details

This JE Pistons 308446S is a 0.040 inch undersize forged piston, specifically made for the Honda CBR 250R. Forged pistons are a step up from cast or hypereutectic pistons, offering improved strength and durability, especially under higher performance conditions or when rebuilding an engine. This piston is designed to be a direct replacement, meaning it fits right into the existing cylinder bore with the appropriate machining for its undersize specification.

JE Pistons is a well-known name in performance engine components, and this piston reflects that reputation. It's constructed from a strong aluminum alloy, chosen for its balance of light weight and robust performance. The 0.040 inch undersize specification means it's intended for a cylinder that has been bored out by that amount to clean up any imperfections or to increase displacement slightly. This is a common practice when rebuilding an engine to ensure a fresh, perfectly round bore for optimal sealing and performance.

When you're rebuilding the engine in your Honda CBR 250R and need a reliable, strong piston, this JE Pistons part is a solid option. It’s important to ensure your cylinder has been properly machined to the 0.040 inch undersize before installing this piston. Always refer to the manufacturer's installation instructions for proper ring gap, piston-to-wall clearance, and assembly procedures.