Yoshimura RS-9T Full Titanium/Carbon Muffler System Review

We test this MX exhaust system

This article was originally published in the July 2017 issue of Dirt Rider.

Yoshimura RS-9T Full Titanium/Carbon Muffler System $1,499Kris Keefer

The 2017 Honda CRF450R was the most anticipated motocross bike of the year. Once I got my hands on ours and took it through the shootout it was time to start testing aftermarket parts on her. The first thing I wanted to try was the Yoshimura RS-9T Full Ti/Carbon Muffler System. We know Yoshimura works closely with the factory Honda team here in the States and have seen the RS-9T muffler on Cole Seely's and Ken Roczen's new Hondas. The Yoshimura RS-9T system only comes in a dual-can setup (no single mufflers are available from Yoshimura) and is a three-piece design. Installation of the system was painless and took 15 minutes.

Once installed and on the track the Honda’s exhaust note turned from a high-pitch 250F-esque to a deep, throaty, more traditional 450 factory racebike sound. The crack of the throttle (or rpm response) is slightly smoother and less crisp, but bottom-end pulling power is increased over the stock muffler. Rolling out of corners in second gear feels like the rear wheel had even more traction than stock and was more controllable while accelerating out of hard-packed corners. The slightly smoother rpm response doesn’t take away the Honda’s excitement anywhere in the power; it just helps you gain a little more control coming out of corners. The midrange pull is healthier than stock, and while the stock system had a tough time pulling third gear in tighter corners, the Yoshimura system will give you an easier time doing so. With just the flick of the clutch lever the Honda will be in the meat of the power once again and have you down the straight in a hurry.

Yoshimura RS-9T Full Titanium/Carbon Muffler System $1,499Kris Keefer

I noticed top-end and over-rev was as good as stock, which is great. It pulls adequately down the straights in second and third gear, and there wasn’t a time I thought to myself, “I need more top-end.” You could tell Yoshimura was focused on bottom to midrange pulling power when it designed this muffler system, and it succeeded in doing so. What is also impressive is that it didn’t lose any top-end and over-rev in the process.

If you are looking to save a little money, Yoshimura offers the stainless-steel/carbon version for $977. I really like the craftsmanship that went into the Yoshimura system. The welds are flawless and the mufflers tuck up inside the side number plates for a stealthy, compact look. If you’re looking for a little more giddy-up and bling from your new CRF450R, the Yoshimura RS-9T system will help you on the track, but your wallet will be not as fat.

Installation 18/20
Performance 47/50
Durability 8/10
Design 8/10
Price 5/10