Pro Circuit T-6 SS Exhaust System for YZ250FX

What it is

• Stainless steel header and mid pipe.
• Aluminum muffler with stainless steel end cap.
• Spark Arrestor capabilities.

Pro Circuit and power are synonymous with each other. They have been producing aftermarket pipes and silencers since the 80’s and continue to be one of the leaders in aftermarket exhaust systems. They offer a variety of different systems for two and four strokes. Since our 2017 YZ250FX doesn’t come with a spark arrestor, we sought after Pro Circuit’s T-6 Stainless Steel complete system to satisfy our need of a spark arrestor. It comes with a head pipe, mid pipe, and muffler featuring a removable spark arrestor screen. The header, midpipe, and end cap are all made of stainless steel while the canister is made of aluminum. Additionally, it comes with pipe springs and anti-seize to keep everything fitting tight.

How it works

• Quieter
• Stronger on top.
• Mellower bottom to mid.

First and foremost, the fit and installation of the Pro Circuit exhaust was simple and easy. Everything lined up perfectly and nothing was out of place. Similarly, the provided exhaust springs and anti-seize made for a perfect fit.

When using the Pro Circuit exhaust with the S/A both inserted and removed, the bottom to mid-range is a little mellower than the stock exhaust. This struck us right away and we were a little at loss if this was going to be a good modification.  It doesn’t have as strong of a pull and it takes a little longer to get going compared to the stock exhaust. Similarly, it doesn’t hit as hard as the stock system. But in taking a step back we realised it could be an advantage or disadvantage depending on the terrain and rider preference. If you are looking to make the bike easier to manage or induce less fatigue, this will do the job.

Similarly, if your riding terrain involves a lot of throttle control and smooth power delivery, the T-6 shines in that area as well. When trail riding on the 250FX, having a little tamer motor is welcomed most of the time. It acts as sort of a traction control system with the smoother power delivery and less wheel spin. In addition, longer trail rides usually result in a large amount of fatigue but again this system will help tremendously with that.

No matter how you ride, once you got into the top end, the power deliver lasted longer and pulled much what feels like further than stock. We could seemingly go forever before hitting the rev limiter making the top end power way more useable.

We rode with both the S/A inserted and removed and the biggest difference was the sound levels. Although, the power was affected by it, it was not as much as we suspected it would be.

A benefit the Yamaha offers is the ability to alter the mapping with the GYTR Power Tuner. Having that is like changing the pipe, yet it doesn’t provide a S/A. However, with the tuner, you can change the mapping so the T-6 system with the spark arrestor runs similar to having the stock exhaust installed. We tested some different maps and we were able to get it to work even a little better than the stock exhaust with stock mapping. Using the tuner we got the bike to hit harder and rev a lot quicker. It lost its smoothness and traction control like feeling but all our testers liked the mapping change better for aggressive or racing type applications where this snappier power was prefered. It is just like jetting to get the most out of the pipe, just digital, quicker and cleaner.

The biggest advantage in getting this system is its spark arrestor capabilities and to quiet the bike for sound restricted riding areas. The USFS approved S/A can either be inserted or removed with one bolt in a matter of minutes. This allows the bike to be legally ridden in a plethora of different areas from the deserts to the mountains. Similarly, several racing series’/events require a S/A to compete and the stock exhaust doesn’t come with one. This allows racers to have a larger selection of events that they can race in.

In addition, the sound is reduced drastically. The stock exhaust is quite loud, almost too loud at times, and the T-6 tones it down a bit without the S/A inserted. Likewise, when the S/A is inserted, it reduces the sound even more. With the T-6 installed, it consistently tested about 1db lower than the stock exhaust on the 94db sound test.

The system costs just over $800, which for a four-stroke, is relatively inexpensive nowadays. Other systems made of more expensive materials and finishes can cost upwards of almost $1100. Although it may lack in the luxurious materials like carbon fiber and titanium, they often work just as good as the more expensive ones while also being more durable with its stainless steel body.

In conclusion, the Pro Circuit T-6 stainless steel exhaust system has its advantages and disadvantages depending on the riding style and rider preferences. But, there are far more advantages to it. Durability, sound reduction and legality make this a winner for us.