Product Report: Doma Racing Yamaha YZ250F Exhaust

Application: 2003 Yamaha YZ250F
Price: $411
Rating: 9

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Developed and produced in Belgium, Doma Racing pipes are imported into the United States by Grant Langston and his father, Gerald. Having tried Doma pipes on both the 125 and 250cc KTMs in the past and been delighted with their performance, we were curious to see how a non-KTM pipe from the rest of the lineup performed. After all, one would expect the Doma pipes for a KTM to be extra gnarly, seeing as how Grant himself uses them exclusively. That being said, we ordered up a unit for our Yamaha YZ250F test bike.

When we first took delivery of the Doma system (complete with a header and muffler), we must admit that we were shocked at the unit¿s overall size. Take a look at the photo: the muffler is at least an inch or two longer than the stocker! Once we inspected the system, however, we understood why the extra girth is required. With a much larger muffler core size, the extra length is needed to maintain an acceptable exhaust note level. The quality of the Doma system is superb, and both the header and muffler bolt on perfectly.

On the track, we were surprised to find that the Doma system sounds just like every other aftermarket pipe we¿ve tried. Because of its length, we were expecting the bike to whisper like a choked-up dual-sport bike, but instead it growls like a full-blown racer. Our test bike required no jetting changes when we bolted on the Doma pipe, which was surprising considering the performance gains it yielded. Low-end power is actually a little softer than stock. If you ride super-tight Supercross-style tracks, the Doma pipe doesn¿t have that super-snappy low-end hit that you might crave. If you ride faster, wider-open outdoor style courses, however, this is definitely the pipe for you! Once the rpms begin to rise, the Doma pipe comes into its own. The pipe packs a great mid-range punch, but top-end overrev is where the exhaust system really shines. Revving the bike further in each gear suddenly becomes possible, and the bike seems to pull forever. Up top, the system yields a full two-horsepower gain from 10,000 rpm on up.

This system is best suited for outdoor tracks, or advanced riders who can keep the rpms up and really take advantage of the power gains this pipe has to offer. We love it.

Stock

RPM Torque Power
6000 13.3 (ft.-lb.) 15.6 (horsepower)
6500 15.4 18.7
7000 17.3 23.1
7500 18.6 26.6
8000 19.1 29.2
8500 19.1 30.8
9000 18.4 31.6
9500 17.8 32.1
10000 17.4 33.1
10500 16.6 33.2
11000 15.3 31.9
11500 14.1 30.9
12000 13.2 30.2
12500 12.6 29.4
13000 11.6 28.6

Doma

RPM TORQUE POWER
6000 13.0 (ft.-lb.) 14.9 (horsepower)
6500 13.8 17.1
7000 15.4 20.6
7500 17.2 24.5
8000 18.8 28.6
8500 19.0 30.7
9000 18.5 31.7
9500 18.0 32.5
10000 17.9 34.0
10500 17.3 34.7
11000 16.8 35.1
11250 16.4 35.2
11500 15.9 34.7
12000 14.5 33.1
12500 13.9 32.5
13000 12.3 30.5

Call 909/719-3227 or visit www.langstonracing.com.

8000 18.8 28.6 8500 19.0 30.7 9000 18.5 31.7 9500 18.0 32.5 10000 17.9 34.0 10500 17.3 34.7 11000 16.8 35.1 11250 16.4 35.2 11500 15.9 34.7 12000 14.5 33.1 12500 13.9 32.5 13000 12.3 30.5

Call 909/719-3227 or visit www.langstonracing.com.