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FMF

Factory 4.1 RCT Muffler

Name: Factory 4.1 RCT Muffler
Brand: FMF
SKU: 041517

$599.99 $476.19 Save $123.80

SKU: 041517

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Overview

The FMF Factory 4.1 RCT is a slip-on muffler designed for the Honda CRF450X, available in a natural aluminum finish with a carbon end cap. It features FMF's Resonance Chamber Technology™ for improved performance throughout the RPM range and offers significant weight savings. The muffler's shorter overall length makes it less susceptible to crash damage and centralizes mass by moving it closer to the motor.

Constructed from aerospace-grade titanium and stainless steel, this single-configuration muffler includes an integrated screen insert spark arrestor and meets AMA Professional Sound Requirements with its quiet insert. It weighs approximately 5 lbs and is manufactured 100% in FMF's Southern California factory.

Show original supplier description

The FMF Factory 4.1 RCT Muffler is engineered to deliver significant performance enhancements to your dirt bike. It utilizes FMF's advanced Resonance Chamber Technology, both internally and externally, to optimize exhaust flow and sound. Constructed from aerospace-grade materials meeting exacting specifications, this slip-on muffler features a durable stainless steel midpipe and a natural aluminum canister, capped with a carbon fiber end cap. It comes with a screen-type spark arrestor, essential for off-road riding, and meets AMA professional sound requirements. The FMF Factory 4.1 RCT is noted for providing massive power gains throughout the entire RPM range and offers substantial weight savings compared to stock systems. This FMF muffler can be used with either an FMF header or the stock OEM header, offering flexibility in customization. It is important to note that this product is intended "For Closed Course Competition Use Only" and is "Not Intended for Street Use." Included with the muffler are the stainless steel mid-pipe, the muffler itself, a spark arrestor, a spark arrestor ring, a muffler washing plug, and instructions. The unit has a listed weight of approximately 5 lbs.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

Brand	FMF
Part Number	041517
Category	Exhaust

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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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