Two Brothers Racing Yamaha YZ450F M-7 Complete Exhaust System

Two Brothers Racing
Yamaha YZ450F M-7 Complete Exhaust System

Two Brothers is like Burger King for exhaust systems: You can get it your way. For example, the systems use a polished stainless steel header, ornate header brackets and a cast-magnesium end-cap. You can have canisters in aluminum, Ti or carbon fiber. We asked for a stainless/aluminum combo, and it came with an approved spark arrestor. Two Brothers also sports a variety of end-cap options to tune sound output and performance. A new option, and our reason for taking a look at this pipe, is the Two Brothers Custom Shop. For an additional $129.95 (free if you buy an exhaust and a Juice Box fuel controller for some fuel-injected bikes), you can have your choice of a variety of canister materials and surface treatments, and multiple colors of end-cap screws and trim parts. You also have a choice of four custom nameplates and the typefaces used on them. Our pipe came with a riding number and verbiage about the pipe being custom made for me and Dirt Rider.

The overall finish of the pipe and the fit is excellent. The joint between the muffler and the midpipe rotates, so getting it all lined up the first time is a little fussy, yet not frustrating. What was frustrating was how loud the pipe was. We ended up running the smallest end-cap for motocross, and even with the spark arrestor the sound was marginal for off-road.

Even with the restricted end-cap the performance was boosted over the stock YZ system. The engine responds more quickly and with more energy leaving turns, and it responds to the clutch easier. The system never came loose or had any leaky joints. The aluminum end-cap bolts are a little on the delicate side, but you really only use those as you're dialing in the system when you first get it. Even the fancy custom nameplate held up well. At $519.98 (without the custom shop options), the pipe is in the price ballpark for a spark-arrested pipe. Still, with the technology and rapid prototyping the company has at hand, we expected something more innovative than a tiny cork at the end of the pipe to control sound in an off-road exhaust. I'd like it quieter for motocross, and without the tiny end-cap tip. This is a quality piece that looks killer, but the sound output slammed the score. -Karel Kramer