Muffler - Keefer, Inc. Tested

Pro Circuit Ti-6 Muffler System (2024 Yamaha YZ450F)

The Pro Circuit Ti-6 Titanium Exhaust System is constructed of titanium throughout the head pipe, mid pipe, and canister while the end-cap is carbon fiber. I wanted the Ti-6 system because I wanted to lose a little weight as the this version of the “6s” allows me to shed almost two pounds off of the…

ByKris KeeferJanuary 5, 20240Comments

Bike Brands Bolt-Ons Exhaust Hard Parts Kawasaki Performance

Pro Circuit Ti-6 Muffler System (2024 KX450)

Aftermarket muffler manufacturers rejoice! The 2024 Kawasaki KX450 has A LOT of room for improvement with its muffler system. The stock muffler is choked up and makes the KX450 feel somewhat lethargic for a 450. Yes, I know what you’re thinking.. “Kris, it’s a 450, how much power do we actually need”? You would be…

ByKris KeeferDecember 17, 20230Comments

Bike Brands KTM

Akrapovic Evolution Slip On System (2022-2023 KTM 450 SX-F)

The Akrapovic Evolution slip on version that comes with the Factory Edition is beautiful work of art. If you’re expecting a ton of added RPM response (excitement) from this slip on system compared to a full muffler system, you will be disappointed. The Akrapovic slip on isn’t an exciting/snappy system that will blow your mind…

ByKris KeeferJune 25, 20230Comments

Bike Brands Bolt-Ons Exhaust Hard Parts Performance Yamaha

Akrapovic Evolution Muffler System (2023 Yamaha YZ450F)

The Akrapovic Evolution muffler system is one of the most beautiful looking systems out there in the market today, is well built, and has quality welds all the way around it. The change of shape in the Evolution muffler might take some getting used to but to me, it is one of the most under…

ByKris KeeferMarch 6, 20230Comments

Bike Brands Bolt-Ons Exhaust Gasgas Hard Parts Performance

Pro Circuit Ti-6 Muffler System (2023 Gas Gas MC350)

The Gas Gas MC350 isn’t a bike that I get to play with that long as the company requires the unit back early so I at least wanted to get a Pro Circuit muffler test in before they snatched the unit back. I have not tested many Pro Circuit pieces on a Gas Gas/KTM/Husqvarna so…

ByKris KeeferJanuary 9, 20230Comments

Bike Brands Bolt-Ons Exhaust Hard Parts Kawasaki Performance

FMF 4.1 Stainless Muffler System (2023 Kawasaki KX250)

The Kawasaki KX250 has undergone some significant engine changes for 2023 and that sparked FMF to make an update to their 4.1 muffler system. The 2023 Kawasaki KX250 engine character has more low end grunt as well as pulling power than last year’s model but it still isn't quite as good as the Yamaha in…

ByKris KeeferDecember 1, 20220Comments

Bolt-Ons Exhaust Hard Parts Husqvarna

To Slip On Or Not To Slip On? FMF 4.1 Slip On Muffler (2023 Husqvarna FC350)

Some muffler questions that get sent to my email inbox usually look like, “which muffler is best for my bike? Is a full system worth the money or can I just get away with purchasing a slip on”? “Is my stock muffler the best muffler option for me”? Instead of trying to keep answering some…

ByKris KeeferSeptember 28, 20220Comments

Bike Brands Bolt-Ons Exhaust Honda KiT Performance

Akrapovic Evolution Muffler System (2021-2022 Honda CRF450R)

I had the initial impression of the Akrapovic Evolution muffler system as I was doing a MotoConcepts/Bullfrog Spas Honda team test. I noticed that they have been running Akrapovic systems on their bikes, so I asked if I could borrow one to see how it worked. Akrapovic's Evolution line is their full titanium muffler system…

ByKris KeeferOctober 21, 20210Comments

Bike Brands Bolt-Ons Exhaust KiT KTM Performance

Akrapovic Evolution System (2021-2022 KTM 250 SX-F)

When you purchase a 2021 KTM 250 SX-F TLD version the bike comes with a slip on Akrapovic Evolution muffler. However, I know that sometimes, certain machines react better to full systems rather than slip ons, we decided to get the full Evolution system to see how it changes the KTM 250 SX-F’s engine character.…

ByKris KeeferAugust 9, 20210Comments

Bike Brands Bolt-Ons Exhaust KiT KTM Performance

FMF 4.1 Muffler System (2021 KTM 250 SX-F)

My son and I have been going back and forth on mufflers for his KTM 250 SX-F and have went though about three until we settled on the FMF 4.1. We have tried the HGS (which was good), a Yoshimura, as well as a Pro Circuit system, but for his riding style and what he…

ByKris KeeferJune 7, 20210Comments

Sign Up to Our Newsletter