Yoshimura R&D of America, Inc.

KX250F 17-20 RS-4 Stainless Slip-On Exhaust, w/ Aluminum Muffler

KX250F 17-20 RS-4 Stainless Slip-On Exhaust, w/ Aluminum Muffler - Main image
KX250F 17-20 RS-4 Stainless Slip-On Exhaust, w/ Aluminum Muffler - View 2KX250F 17-20 RS-4 Stainless Slip-On Exhaust, w/ Aluminum Muffler - View 3KX250F 17-20 RS-4 Stainless Slip-On Exhaust, w/ Aluminum Muffler - View 4
$420.92 $619 In stock

Category: Signature Series Exhaust System

The work that went into developing the RS-4 muffler has paid big dividends in Off-road Racing; winning multiple Supercross and Motocross titles since it's inception. We've developed the current generation RS-4 based on that research & development, and the result is a unique design that provides an unrivaled combination of power and quiet exhaust tone. The RS-4 features a Polyresonant duplex chamber and two-staged stepped baffle for increased performance, while a carbon cone end cap finishes off its innovative styling.

  • Pentagonal-shaped sleeve
  • Front muffler cap functions as a polyresonant chamber which helps reduce noise
  • Two-stage stepped baffle
  • Carbon fiber end-cap
  • Stainless steel tail-pipe
  • Repack Kits, optional Inserts and Spark Arresters are available for all models
Before you pay

Check the method and total at checkout.

When it ships

Allow for processing time as well as the journey to you.

Standard Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.

View policy
If you need a refund

Keep your order number and contact the store to start.

Please contact us for the refund processing timeframe before returning an item.

View policy
Delivery costs

Review the cost for your destination and chosen service.

Standard Shipping · United States: $0.00

Express Shipping · United States: $3.99

View policy
Returning an item

Check the return conditions before sending anything back.

United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.

View policy

Customer Reviews (5.0 / 5 · 5 reviews)

Harper S. ★★★★★

Bolted it on in about 20 minutes and the fitment is spot-on for the 17-20 frame. The stainless build feels solid, and the sound has that deep, race-ready bark without being obnoxious on the trail.

Elizabeth R. ★★★★★

The aluminum muffler is noticeably lighter than the stock steel one, and it bolted right up to my KX250F in about twenty minutes. The sound is deeper and more aggressive now, but still passes the 96db track noise test.

Lucy ★★★★★

I was worried the slip-on would be too loud for my local track, but the RS-4 actually has a really clean, deep tone that isn't obnoxious. The stainless construction feels solid and the muffler itself is noticeably lighter than stock when I held them side by side. Installation was straightforward and

Related Products