FMF Racing Factory 4.1 RCT Titanium Full System - 2019 KX250

Vital Rating:
Tested: FMF Racing Factory 4.1 RCT Titanium FS for KX250
Vital Review
The Good
Increased power across the board, increased throttle response
The Bad
Doesn't really boost any part of the power more than any other and doesn't add any overrev.

For this test of the FMF 4.1 system on our 2019 Kawasaki KX250, we tapped into one of our testers, former supercross racer Steve Boniface. He's been riding our KX250 and will be turning it into a project bike, but in the meantime we asked him to give us feed back on some of the individual parts, such as this full exhaust system.


  • Available in Blue Anodized Titanium Muffler with Carbon End Cap
  • Power gains throughout the RPM range.
  • Weight savings
  • FMF uses the highest quality proprietary blend of alloy grade titanium made especially to our standards.

On The Track

With OEM pipes being as good as they are these days, installing an aftermarket pipe can sometimes just mean moving the power around rather than increasing it. But, just like we have found on the 2019 YZ250F that we tested earlier this year, the FMF Factory 4.1 for the KX250 doesn’t really change the the stock power curve. It does, according to Boniface, boost the power just a little across the board. There isn’t a huge hit on bottom, in the mid, or on top - just a consistent increase in torquy-ness throughout the powerband. Boniface also noticed more throttle response that made it easier to jump obstacles right out of corners and this also gave him more control of the bike.

The only real downside to the FMF system is that it doesn’t focus it’s increase in power in any section of the rpm range. Meaning, rather than a small increase in power across the board, some pipes concentrate the increase of power on the bottom to give the bike a stronger torque character, or they can concentrate the power on top to make a bike rev out longer and stronger.

Overall, the FMF Factory 4.1 helped the 2019 KX250 wake up a little bit and gave it an even spread of increased power. This is the pipe for you if you really like the way the KX250 makes power stock. If you are a lugger and just want more bottom, or if you rev your 250F to the moon, this might not be exactly what you are looking for. 


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FMF Racing Factory 4.1 RCT Titanium Full System - 2019 KX250
Complete Exhaust System
Engine Type
Fits Model Year
Fits Brand
Fits Size
• Incorporates the latest in FMF Resonance Chamber Technology both internally and externally
• Shorter overall length that is less susceptible to crash damage and moves the muffler closer to the motor to centralize mass
• Constructed from only aerospace grade materials - the highest quality proprietary blend of alloy grade titanium
• Massive Power gains throughout the RPM range
• Huge weight savings
• New RTS (Rapid Tuning System)
• Notice: Closed Course Use Only
• Type: System
• Configuration: Single
• Construction: Titanium
• Finish: Blue Anodized
• Midpipe: Titanium
• Endcap: Carbon
• Spark Arrestor: Screen Insert (included)
• Carb Warning: no
• Quiet Insert: 94dB Insert (included)
• Header Construction: Titanium
• Header Type: MegaBomb
More Info
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