FMF Factory 4.1 RCT Slip-On Muffler 045628 — KTM / Husqvarna / GasGas 2018-2023

Product Description

The FMF Factory 4.1 RCT Slip-On Muffler is the ultimate exhaust upgrade for the discerning rider. Featuring FMF’s patented Resonance Chamber Technology (RCT), this muffler utilizes a specialized core shape to significantly lower decibel levels while actually increasing power output. By maximizing internal volume through advanced ducting, the RCT system ensures smooth, potent power gains throughout the entire RPM range.

Engineered with Factory Forward Engineering, the muffler is positioned closer to the engine to centralize mass, improving handling and offering better protection against crash damage. This high-performance slip-on is constructed with a durable aluminum canister and a premium carbon fiber end cap, blending lightweight materials with professional-grade durability. It arrives ready for any environment, including a QuietCore 94 dB insert and a spark arrestor for trail compliance.

Top Features: FMF Factory 4.1 RCT Slip-On

• Resonance Chamber Technology (RCT) lowers sound output while boosting power
• Factory Forward Engineering design centralizes mass for improved handling
• Lightweight aluminum canister with high-strength carbon fiber end cap
• Includes QuietCore 94 dB insert and spark arrestor for maximum versatility
• Compatible with both stock headpipes and FMF performance headers
• Proudly made in the U.S.A. and meets AMA/FIM sound requirements

Please review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.

Fitment List

Frequently Asked Questions

Q: Is it easy to remove the spark arrestor?
A: Yes, the rear end cap is designed for quick access, requiring the removal of only four screws to swap or remove the spark arrestor and tuning tip inserts.

Q: Will this improve my bike's throttle response?
A: Absolutely. The combination of RCT technology and reduced weight over the stock muffler helps the engine rev more freely and improves overall throttle response.

Expert Pro-Tip: To keep your Factory 4.1 RCT performing at its best, plan on repacking the muffler every 20–30 hours of hard riding. A burnt-out packing will not only make the bike louder but will also negatively impact the power delivery and can eventually lead to casing damage from excessive internal heat.

Recommended Pairings:
o KTM 4-Stroke Performance Parts
o Husqvarna 4-Stroke Performance Parts
o Premium Motorcycle Chemicals & Lubricants

At Moto-House MX, we carry the best brands in motocross and off-road performance. Our team has over 40 years of experience helping riders get more out of their bikes. Every order ships fast from our Central Florida location.

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