Wiseco 03-07 KTM 450EXC/MXC/XC-W 121 (4942M) Piston Kit

Wiseco 03-07 KTM 450EXC/MXC/XC-W 121 (4942M) Piston Kit

Marsoni

M251S

$179.59

Get it in 3 business days with 1 day shipping. Friday, May 29

Wiseco 03-07 KTM 450EXC/MXC/XC-W 121 (4942M) Piston KitThe Wiseco team has remained at the forefront of powersports performance through every era and evolution, including the development of high performance 4 strokes. Today, Wiseco's forged 4 stroke pistons are designed for each specific engine application and built to the tightest tolerances for the ultimate combination of performance and strength. Proven at every level of riding, Wiseco 4 stroke pistons are ready to deliver the power and reliability

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Called around for quotes to get them replaced and everyone was quoting over $2k just for bellows. Figured I’d give it a try. The rubber is good quality and feels soft. Time will tell but this is an easy job if you’re mechanically inclined. Make sure you replace the plastic water pickup fitting while you’re at it. Found mine to be cracked on disassembly and had to wait for a new one. Should be a easy 3-4 hour job if your not doing the bearing and only doing bellows

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Reviewed in the United States on August 26, 2024

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Ben

Los Angeles, US

★★★★★ 3

Just ok

Qualities OK, but for Marine applications might want better

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Reviewed in the United States on August 3, 2025

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Barbara S.

West Palm Beach, US

★★★★★ 5

Great quality

Just as described.

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Reviewed in the United States on July 22, 2025

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Paul Kirchberger

Pawtucket, US

★★★★★ 5

Bellows kit review initial inspection’s

Very good quality. The hose clamps were event the better ones you have to pay extra in most cases.

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Reviewed in the United States on April 6, 2025

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Henry Williams

Fort Morgan, US

★★★★★ 5

Durable and well fitting

Durable and well fitting. I drive a Honda Accord 2014 and when the under engine covers started falling off I used these to replace the ones that came off. They work well and the prying tool made replacing the retainers easier.

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Reviewed in the United States on January 18, 2026