Long known for equipping many factory teams in numerous World Championship series (both on- and off-road) with exquisite exhaust systems since the '80s, Arrow Special Parts S.p.A. in Italy has used that experience to help lead development of a new line of exhaust systems for many of the latest sportbikes. Part of that new lineup is the new Gp2 series of exhausts that take much of their design inspiration from MotoGP's new Moto2 spec class. Unlike the company's superb (but also very expensive) full competition exhaust systems, the Gp2 is primarily a slip-on model (with some variants also including a mid-pipe).
We decided to try one of Arrow's latest Gp2 units on our '10 Yamaha YZF-R6 test bike. The Arrow slip-on replaces the R6's short, stubby stock muffler that attaches to the under-engine exhaust chamber, and it's made entirely of titanium, so the unit is very light; however, the stock muffler is also made from titanium, so it's not exactly heavy either. Weighing in at a featherlight 3.44 pounds, you'd think that the Arrow Gp2 cuts off at least a handful of pounds from the stock unit, but it undercuts the stock Yamaha muffler by only 1.04 pounds - a graphic example of how far many stock components have progressed as far as design and development.
However, there's no doubt that the Arrow pipe looks far better than the bland-looking stock muffler; as is typical of all Arrow products, the quality of construction is absolutely top-notch, with light-gauge titanium bonded together by welds so smooth and perfect that they are literally an art form. The round canister is short and stubby, sporting a slash-cut tip with rolled edges that give it the real MotoGP look. The canister comes with a "dB killer" insert for noise reduction that attaches to the exhaust tip with a flat allen-head screw. Our only gripe was that the Arrow label on the canister was lifting and peeling a bit, a stark contrast to the superb quality of the rest of the unit.
Installation for the slip-on was expectedly easy, as the stock muffler attaches directly to the under-engine exhaust collector chamber. The Arrow Gp2 slip-fits over the stock muffler fitting on the under-engine chamber with a high-quality stainless steel screw-tension clamp, and a simple tab on the pipe attaching to the stock mount on the right-side footpeg bracket. The muffler slip-fits snugly over the pipe and is secured by a single spring-tension clasp.
To be honest, we weren't expecting any power increase from the Arrow Gp2 slip-on, especially for just replacing the muffler on a 600, which doesn't have the comparative power gains of a literbike when changing exhausts. To our pleasant surprise, the Gp2 actually helped a bit on top, with some slight power gains from 10,000 rpm on up to a power peak of 104.2 horsepower at 13,750 rpm, a 1.3 horsepower boost. With the dB killer insert installed, peak power dropped to just a tad over stock, but the exhaust note was obviously better than the standard muffled shriek; however, even without the insert, exhaust noise wasn't excessive until you reached the upper five-figure portions of the powerband.
Arrow's Gp2 slip-ons are available for most current sportbikes with under-engine exhausts; the R6 unit we tested retails for $399.00.