FMF Racing's Factory4.1 SL Slip-On delivers elite race-proven performance for off-road and motocross riders seeking maximum power gains. Drawing on three decades of championship-winning engineering, this exhaust is constructed from premium titanium and finished in striking blue anodised plating. The slip-on design features a high-strength stainless steel midpipe and endcap, optimising performance across the RPM range while remaining lightweight. Designed for closed-course use, it includes a 94dB insert for sound regulation and comes equipped with a spark arrestor, offering both compliance and versatility.

Features

• Race-developed performance with proven horsepower increases
• Lightweight titanium construction and blue anodised finish
• Stainless steel midpipe and endcap for enhanced strength
• Includes 94dB quiet insert and spark arrestor screen insert
• Slip-on configuration enables quick installation
• Closed course use only

Specifications

• Item ID: 044235
• Type: Slip-On
• Configuration: Single
• Construction: Titanium
• Finish: Blue Anodised
• Midpipe: Stainless Steel
• Endcap: Stainless Steel
• Spark Arrestor: Screen Insert (included)
• Quiet Insert: 94dB Insert (included)
• Weight: 5.2 lbs (2.36 kg)
• Carb Warning: No

Vehicle Fitment

Yamaha

• WR250F (2007–2013)
• WR450F (2007–2011)
• YZ250F (2006–2009)
• YZ450F (2006–2009)