Yoshimura RS-4 Signature Series Full Exhaust System

Item Number: 338943


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Product Description


Yoshimura RS-4 Signature Series Full Exhaust System

Yoshimura Signature Series exhaust components are the answer for riders faced with ever-tightening noise and emissions regulations at the federal level. All Signature Series components are independently tested, documented, and marked as required by state and federal regulations as CARB/EPA-compliant.

The work that went into developing the RS-4 muffler design paid big dividends during development in AMA Pro Racing. That research was directed at developing the RS-4's unique design that provides an unrivaled combination of power and a quiet exhaust note. The RS-4 muffler features a polyresonant duplex chamber, a two-staged stepped baffle and an innovative carbon cone end cap.

  • Pentagonal-shaped sleeve
  • Front muffler cap functions as a polyresonant chamber which helps reduce noise
  • Two-stage stepped baffle
  • Carbon fiber end-cap
  • CNC mandrel-bend header and tail pipe
  • Includes instructions and all required installation hardware
  • 80dB EPA noise emissions compliant

Spec Details
CARB Approved Yes
Country of Origin USA
Header Construction Varies (make selection above)
Muffler End Cap Carbon Fiber
Muffler Sleeve Varies (make selection above)
USFS Spark Arrestor Varies (make selection above)

Vehicle Fitment

Fitment is guaranteed or your money back plus free return shipping. Don't waste time installing a product that doesn't fit. We worked hard ensuring that this product is an exact fit on the vehicles listed below.

Arctic Cat

  • Wildcat 4 1000 2013-2014
  • Wildcat 1000 2012-2014
  • Wildcat 1000 X 2013-2014


  • CRF250R 2010-2013
  • CRF450R 2009-2012


  • 250 SX-F 2012-2015
  • 350 EXC-F 2012
  • 350 SX-F 2011-2015
  • 350 XC-F 2014-2015
  • 450 SX-F 2012-2015
  • 450 SX-F Factory Edition 2012-2013
  • 450 XC-F 2013-2015


  • KX250F 2010-2016
  • KX450F 2009-2015


  • RZR XP 4 900 2012-2013
  • RZR XP 4 900 EPS 2012-2013
  • RZR XP 4 900 Jagged X 2013
  • RZR XP 900 2011-2013
  • RZR XP 900 EPS 2012-2013


  • RM-Z250 2010-2017
  • RM-Z450 2008-2017
  • RMX450Z 2010-2011, 2017


  • WR250F 2015-2017
  • YZ250F 4-Stroke 2007-2017
  • YZ250FX 4-Stroke 2015-2017
  • YZ450F 2010-2017

Customer Reviews

Questions & Answers

  • Will this also fit the 2014 350 XCF-W?

    By: KTMrider

    Yoshimura did not produce an exhaust to fit the that particular KTM model. FMF does produce an exhaust system to fit the 2014 KTM 350 XCF-W in the form of the Factory 4.1 RCT Full Exhaust System. We have that FMF 350 XCF-W exhaust system with a plain or blue-anodized muffler sleeve with a titanium end cap, or one with a blue sleeve and a carbon fiber end cap. All of those KTM FMF exhausts come with a MegaBomb header.

    By: Staff