Research Guide- Aftermarket Exhausts
I read all the reviews, watched all the videos and have consolidated the top takeaways and research links in one convenient article.
First things first, before making any big purchase, I always start by identifying the job I am hiring a product to do. What improvements am I looking for? Which is the best available option at the best price possible? I identified two jobs for the exhaust. 1) Power, and 2) Looks.
JOB #1: POWER: My search for more horsepower is not a vain quest to simply feed my ego (but there is some of that). I wanted extra power to help me get over obstacles located immediately out of tight corners, and I wanted to extend the rpm range in each gear. I ride a 250F, and it is oh so close to being the perfect bike for me. If an aftermarket exhaust system would give me that extra power and range I was looking for, it would be perhaps the biggest bang per dollar investment I could make for my YZ 250F.
JOB #2: LOOKS: Let’s be honest...who doesn’t love it when their bike looks factory? Approaching a bike that looks factory somehow summons a sense of confidence and excitement. Few things make your bike look factory like an aftermarket exhaust.
THE CONTENDERS: (links will jump you to specific section)
Side Notes:
As sweet as titanium is, stainless steel is less expensive, more durable, and performs the same. Yes, Ti weighs less but most of us have more than that amount of weight to lose around our bellies.That said, if your budget can handle the Ti version, go for it! They look amazing.
I wanted to include sound as part of the review guide but its difficult to compare apple to apples with online videos as everyones recording equipment and surroundings is different.
BILL’S RE-13
RATING: 3/5 STARS
When buying a Bill’s pipe, it’s important to understand the heritage of what you are buying. Bill’s is one of the original pioneers of performance pipes in the Moto industry. Swap did a great job interviewing Bill and I definitely recommend you watch it. Swap-Bill’s Interview
Bill’s pipes has powered several MX legends, including Bradshaw, Henry, Lamson and Pastrana. There’s just something about a Bill’s pipe that makes them stand apart. The Bill’s vibe is a fusion of MX heritage, blue collar work ethic, the Privateer-spirit, and Pro-proven performance.
Usually a company as decorated as Bill’s would be more prominent on people’s radar. However, for some reason you don’t see a lot of Bill’s pipes being advertised, mentioned, or represented on bikes. Heck, for that matter, they don’t even have a website. The odd thing about all of this…the rareness of their availability kind of makes me like them even more.
RESEARCH SUMMARY: Doing research on the RE-13 was more difficult than the other brands. There really aren’t many reviews available on the RE13, and what I could find didn’t really tell me anything that made it stand out. Despite the obvious gaps in reviews and available information, I did find a lot of confidence that the EBR Performance team chooses Bill’s to power their race bikes. If you choose to do some of your own research let me save you some time and tell you that the best way to get a hold of them is by email (info@billspipes.com). Why? Because as odd as it sounds in today’s web-centric universe, they don’t have a website or a phone number. Also, at the time I did my research, the only way to purchase was to either provide a CC number over email or request them to call and provide a CC number over the phone. This is why I rated it at 3 stars.
FEATURES:
Independently tested by EBR to produce better useable power versus FMF 4.1 (claimed).
Lightweight Carbon fiber end-cap.Stainless steel mid pipe / head pipe, Aluminum muffler
Unique aluminum muffler shape allows for added volume & clearance
Coned inlets for greater packing volume
JOB #1, POWER: Similar to most exhaust companies, Bill’s doesn’t provide any dyno data, but in my correspondence with Bill’s they confirmed that EBR Performance has tested against other big-name pipes and the RE-13 outperformed the other brands.
JOB #2: LOOKS: The RE-13 design is aggressive and distinctive. I also like the fact that you don’t see Bill’s pipes on every other bike at the track like you do with some of the brands.
DECISION: I trust that EBR did their homework, and I really like the RE-13’s look. I am also a big fan of Bill’s heritage. That said, I have to be honest and say that the lack of available reviews coupled by the difficulty of purchasing were the primary reasons I ultimately decided to not purchase the RE-13 (at this time). I rated the Bill’s at a 3, but it’s score that could quickly springboard to a 5 if they got their pipe out to some reputable reviewers and made it easier to purchase.
INFORMATIVE LINKS:
PRO-CIRCUIT T-6
RATING: 4/5 STARS
Pro-Circuit is one of the most sought after and respected brands in Moto, and rightfully so. Mitch and his team have built the ProCircuit reputation on performance and championships.
RESEARCH SUMMARY: Reviewer’s agree that the T6 helps improved bottom to mid range power without sacrificing top end.
I called Pro Circuit to talk about the T-6. According to the PC team, the T-6 is designed to produce better power throughout the entire RPM range. They didn’t have any dyno charts, but as we all know, Pro Circuit’s reputation is solid, so I don’t have any reason to doubt what they told me. Pro Circuit’s reputation for excellence combined with the positive reviews put this pipe in the top three for consideration.
FEATURES:
Aluminum canister, stainless steel head pipe, mid pipe and end-cap
Asymmetrical muffler configuration for increased packing volume
Machined mid-pipe to head-pipe joint for a better, leak free fit
TIG precision welding
JOB #1, POWER: Pro Circuit didn’t have any dyno data, but it’s hard to argue that their exhaust systems don’t produce better power across the entire RPM range.
JOB #2: LOOKS: The titanium version of the T-6 looks amazing, but the stainless version is merely one step above stock. Perhaps I would like the looks a lot more if I had seen it in person, but like many of you, my comparative research is largely constrained to online. I think they should used the carbon fiber endcap with a more aggressive decal set.
DECISION: I gave it 4 stars primarily because the looks are a little understated. Looks aside, I still may have purchased one, but the COVID supply chain put them out of stock.
INFORMATIVE LINKS:
FMF 4.1
RATING: 4.5/5 STARS
The FMF 4.1 exhaust is synonymous with the success of the Star Racing Yamaha team, so when considering my application to YZ250F, it’s virtually impossible to not strongly consider the 4.1 system.
Star Racing Yamaha spares nothing to make sure they have the best parts and products on their bikes which lends instant credibility to FMF.
RESEARCH SUMMARY: The 4.1’s exhaust tone and looks are spot on. Regarding performance, the reviewers generally agree that the 4.1 improves the bottom and mid range versus stock without sacrificing any over-rev from stock systems. Another added benefit was it’s ability to improve gearing gaps so you’re not left in a compromised gear (not too high, not too low) out of corners.
FEATURES:
Shorter overall length moves weight closer to the motor to centralize mass and less exposed in a crash.
Constructed from aerospace grade materials
Natural Aluminum with Carbon Fiber End Cap
Features FMF’s highest quality proprietary blend stainless steel
JOB #1, POWER: I called FMF and they told me the 4.1 will provide added responsiveness and power throughout the RPM range versus stock. However, there isn’t any dyno data to quantify the increase. That said, it’s hard to argue with their top level results.
JOB #2: LOOKS: The stainless version of the 4.1 does a great job at retaining all the same design cues as the titanium version with the exception of the blue tone. This is one of the best looking exhausts on the market.
DECISION: Since I own a Yamaha and I see FMF on the top pro-level Yamaha bikes, the FMF appears to be the “safe” bet. The FMF performs, and it definitely looks the part with the carbon fiber endcap and factory looking decal set. I was willing to put the FMF as a final contender but unfortunately due to the The Covid supply chain issues they were out of stock. If you can get your hands on one, I would definitely put it in your top two considerations.
INFORMATIVE LINKS:
DR. D NS-4
RATING: 3.5/5 STARS
Dr D exhausts are known for their position as high-performance exhaust systems at a reasonable price. The reasonable price reputation can be immediately seen in their price versus other exhaust systems. Dr. D’s high-performance reputation is a direct result of Doug Dubach’s unique R&D skillsets which are powered by his experience as a top-level pro and test rider. I like Doug’s approach. He doesn’t chase dyno data. He anchors his R&D with relentless on-the-track testing until he can figure out a way to improve the bike’s performance.
Another thing I really like about Dr.D’s exhausts is that he includes sensible design features, like removable bolts (not rivets) at the inlet cap for easy repacking versus having to send it back in or purchase special tools.
RESEARCH SUMMARY: Common opinions include improved bottom end and mid-range without sacrificing top end or over-rev. Reviewers also commented on improved performance out of corners, faster throttle response, and better transition through the power curve and gears.
JOB #1, POWER: Online reviews state more power throughout the RPM range and outperformed expectations, especially since the Dr. D pipe is nearly $200 less than other options in this review.
JOB #2: LOOKS: From what I read online, the exhaust tone is what you’d expect from a performance pipe, however, (for me) I think the looks fall short of wanting to give your bike the “double take” look.
DECISION: The only thing holding me back from going this direction was feedback from a local pro that had a durability issue with his Dr. D exhaust. Since Doug is obsessed with details, I’m sure Doug and his team have addressed any reliability issues that may have occurred, but it did make me a little hesitant to put the Dr. D system at the top of my considerations.
INFORMATIVE LINKS:
HGS
RATING: 3/5 STARS
HGS is not a well-known brand in the US, so I found myself caught in the intersection of intrigue, and hesitation.
One of the cool aspects of the new World SX program is that we get introduced to more European Moto brands. One of those brands we are seeing more of is HGS. Like I said, I am intrigued, but when I’m laying down this much coin, I would like to see more reviews and write-ups and as of now there simply isn’t enough to make me want to spend my hard-earned cash on one of their systems.
RESEARCH SUMMARY: HGS has been around since 1988, managed by a multi-generational Moto family. With HGS being a Euro brand, you will need to contact Bud Racing to get your hands on one. Website: Bud Racing USA
JOB #1, POWER: According to Kris’ review, the HGS exhaust improves the low to mid power range without sacrificing the range of each gear. He also mentions that the KTM 250F became more playful in tight areas of the track thanks to the HGS exhaust.
JOB #2, LOOKS: HGS definitely has a euro look. It looks clean and simple. I just wished it looked a little more aggressive. Even though my #1 job I’m hiring it to do is performance, I want the look to compliment the performance. In my opinion the looks don’t match the performance characteristics of the exhaust.
DECISION: As much as I trust Keefer’s reviews, I would like to see more reviews, and I think the design is sub-par. I decided to pass.
INFORMATIVE LINKS:
Akrapovič
RATING: 5/5 STARS
For me, Akrapovič is one of those brands I’m aware of, but don’t know much about. After spending some time looking into them I can see why the US Factory KTM team and multiple top MXGP teams have partnered with Akrapovič.
Saying your “top tier” is one thing. It’s another to put your money where your mouth is. To get a quick intro to Akrapovič, it’s worth taking 5 minutes to watch the following video: AKRAPOVIC INTRO VIDEO
RESEARCH SUMMARY: Akrapovič manufactures premium exhausts for both the motorcycle and performance car markets. They pride themselves in “performance-first design”, which is comprised of sourcing premium materials, uncompromising craftsmanship, , continuous innovation, and trustworthy durability. Remember how I said putting your money where your mouth is? Well, to prove their commitment to excellence, Akrapovič, owns their own in-house titanium foundry and metallurgical laboratory. It’s investments like this that gives you a level of confidence that’s difficult to replicate.
Common statements from testers of the Akrapovič system:
Great job at creating traction on the bottom end while providing extended power on mid to top.
Excellent build quality
Nearly two pounds lighter than stock
Unique sound
Excellent performance
JOB #1, POWER: Dyno Data: Akrapovic Dyno Data Link.
JOB #2, LOOKS: For some the look can be a little polarizing, but I really like it. Everything about it is premium. It’s the only exhaust without a carbon fiber end cap that I like.
DECISION: Akrapovič unapologetically believes that they manufacture the finest exhaust systems on the planet, and they aren’t afraid to prove it.
Unfortunately, Akrapovič exhausts are priced above my budget. That said, if you have the budget and they are in stock, I wouldn’t hesitate on picking one up!
INFORMATIVE LINKS:
YOSHIMURA RS-12
RATING: 5/5 STARS
Perhaps of all the brands listed in this research guide, I was most surprised to hear that nearly every industry insider I spoke with praised the quality and commitment of Yoshi exhausts and put them at the top of their recommendation list. I had never owned a Yoshi exhaust before, so I was excited to see what all the hype was about.
RESEARCH SUMMARY: The development of the RS-12 was a 2+ year endeavor and prior to production, they tirelessly tested and refined it with pro riders during the heat of competition.
I respect purpose-built design and similar to the efforts made by Akrapovič, the RS-12 is the epitome of purposeful design. For example, take a look at the following examples of the efforts they put into the design:
Each side of the RS-12’s asymmetrical shape has a purpose. The flat inside wall of the exhaust maximizes tire and brake caliper clearance while the outside edges maximize volume resulting in better longevity and increased performance.
The matte black carbon endcap not only looks like it was made in Tony Stark’s lab, but it’s also highly functional. In the case of a crash, the endcap can be replaced independent of everything else by simply twisting a bolt. The design is genius, and extremely practical.
Precision taper-fit technology. Rather than a slip-fit, they opted for machined joints which results in 50% more engagement which means a more precise fit.
Viton grommet. What is Viton you ask? Viton is a space-age Fluoroelastomer compound engineered by DuPont (Viton). It has a broad applcation base including automotive and aerospace. It’s unique material makeup allows it to maintain uncompromised performance in harsh environments, especially when in proximity to high-temperatures. Yoshimura’s use of a Viton grommet may seem like overkill, but to me it showed that they were willing to optimize every square inch of the RS-12’s performance.
JOB #1, POWER: Although dyno tests aren’t always a direct reflection of on-the-track performance, it is nice to compare apples to apples in a controlled environment. Yoshimura sone of two companies that has dyno data. You can see that data here.
JOB #2, LOOKS: The decal set is could be slightly better, but I like the red, white, and blue combo. Makes me feel patriotic. I think the matte black carbon endcap is the best of all the exhausts.
DECISION:
The RS-12 looks great, sounds angry, performs amazingly well, is made with the best materials possible, and was developed with an uncompromising commitment to precision.
The more I looked into the features of the RS-12 and compared it to all of the other options (while also considering availability) there were simply too many positives to pass up for the price. I called my local shop and immediately put one on order.
INFORMATIVE LINKS: