MBRP AT-6402SP Slip-On Exhaust System for 87-04 Yamaha YFM 350X Warrior

Vehicle Fitment

• 1987-2004 Yamaha YFM350X Warrior (ATV)

Fitment Notes

• This is a **slip-on** muffler upgrade -- attaches to existing midpipe; does not replace all exhaust hardware.
• Sport Series "SP" -- designed to offer a more aggressive sound, improved flow, while retaining usable noise levels.
• Includes spark arrestor (USFS approved) built into the muffler.
• Made of aluminized steel with black powder coat finish; polished stainless or black end cap (depending on variant).
• Bolt-on with clamp or flange connection; some models may require minor alignment or adjustment.

Features

• Straight-core muffler for less restriction and improved exhaust flow
• Black-coated aluminized steel body with corrosion-resistant finish
• Spark arrestor built-in for legal use in regulated areas (USFS)
• Black or stainless end-cap options for aesthetic styling
• Sport-tuned sound -- deeper tone at higher RPMs, mild under idle
• Lightweight -- reduces some weight vs stock muffler
• Designed specifically to match the YFM350X muffler interface and hardware pattern

Specifications

• Part Number: AT-6402SP
• Type: Slip-On Sport Muffler / exhaust
• Core Type: Straight-core
• Material: Aluminized steel with black powder-coat / corrosion protection
• End Cap: Black or polished (application dependent)
• Spark Arrestor: Integrated USFS-style screen included
• Sound Profile: Sport / mild aggressive
• Fitment: 1987-2004 Yamaha YFM350X Warrior ATV

Included Components

• 1x AT-6402SP Sport Series Slip-On Muffler (with built-in spark arrestor)
• Clamp or flange hardware for attachment (as per model)
• Installation instructions and torque specs

Product Description

The **MBRP AT-6402SP** Sport straight-core slip-on muffler is designed for the **1987-2004 Yamaha YFM350X Warrior** ATV. This upgrade provides improved exhaust flow and a sportier tone while retaining practical noise levels. Because it's a slip-on, it connects to your existing midpipe--maintaining much of the original layout and fitment ease.

Constructed from aluminized steel with a black powder-coated finish, it balances durability and cost. The inclusion of a USFS-approved standalone spark arrestor makes it legal for many trails and restricted zones. Its black or stainless end-cap styling complements the ATV's look. Installation is straightforward with clamp or flange mounting, and the muffler comes with all necessary hardware.