FMF Factory 4.1 Titanium Exhaust

APLICATION: Most late-model mxers (Tested here on the ’08 YZ250F)

PRICE: $849.99

MOTOCROSS.COM RATING: 9

CONTACT: www.fmfracing.com

            FMF has been around for quite a while now and over the years have established themselves as one of the leaders in the world of aftermarket exhaust systems. Ever since four-strokes have become the dominating bike on the market, FMF has been at the forefront of technology, producing high-quality innovative designs that help to both improve the power of the bikes while reducing weight at the same time. We recently took delivery of the company’s latest exhaust for the 2008 YZ250F, the Factory 4.1 full-titanium system with a Megabomb header.

            Made completely from titanium, the Factory 4.1 system is one of the lightest full systems available on the market today. It features a machined aluminum hanger, re-packable muffler can, and the patented Megabomb header. The system attaches to the cylinder with a combination of springs and bolts that help to reduce vibration and hold the system securely in place. These springs also make fitting the system to the bike remarkably easy. Finally, depending on your preference, the muffler is available in both natural color and anodized blue.

            Out on the track, the Factory 4.1 system does an excellent job at boosting the power on the YZF. In stock form, we found that the bulk of the Yamaha’s power could be found in the middle portion of the powerband, with the low end and top end lacking somewhat. With the Factory 4.1 system bolted on, the anemic low-end power was boosted considerably, making the bike easier to ride, as we didn’t have to always be in the sweet spot of the powerband. The other portions of the power—mid to top—were also beefed upped with the FMF system installed, making the bike rev out further and carry each gear longer. What we liked the most, though, was the fact that we already mentioned—the beefier low-end grunt. As for durability, the FMF system stood up to nearly anything, and in the event of it wearing out, it can easily be repacked with packing sold by FMF.

RATING

            Overall, we were impressed with the FMF Factory 4.1 system. It did exactly what we wanted it to do to the YZ250F, boosting the overall power and mostly increasing the low-end portion of the powerband. At the end of the day, this system makes riding the YZ250F more enjoyable, and that’s exactly what we look for when testing products.