MC Tested: Yoshimura R-77 Slip-On

By Ari Henning, Photography by Yoshimura R&D

Ditching your bike's stock muffler-and the heavy and restrictive catalytic convertor it contains-in favor of an aftermarket slip-on is one of the easiest ways to shed weight while improving the look and performance of your ride. But as state and federal agencies explore additional methods of reducing air pollution and greenhouse gases, bikes are coming under increased scrutiny. Thus your sweet-sounding slip-on may soon fetch you a hefty fine and/or a fix-it ticket.

According to federal anti-tampering laws and state gross-polluter laws, altering any part of a vehicle's emissions system is illegal. So why is it becoming an issue now? With increasingly stringent emissions legislation working its way through the pipeline (California Senate Bill 435 is a prime example), the police and DMV may soon start enforcing those laws, which will essentially require that all bikes operated on public roads retain their stock exhaust systems.

This inevitable scenario will be a headache for performance-minded riders, and could spell disaster for exhaust manufacturers. That won't be the case for Yoshimura R&D, however, which has already released an emissions-compliant slip-on. The R-77 muffler incorporates Yosh's own three-way catalytic convertor, which effectively curtails the three most offensive emissions: nitrogen oxides, carbon monoxide and unburned hydrocarbons. The pipe is certified by the California Air Resources Board (Executive Order Number K-004) as legal for on-road use. Due to the cost of homologation and packaging restraints, the CARB-approved R-77 is currently only available for 2008-2010 Honda CBR1000RRs.

According to the report submitted by the testing center that homologated the pipe, the Yosh pipe is actually cleaner-burning than the Honda's stock exhaust. The combined amount of unburned hydrocarbons and nitrogen oxides coming from the tailpipe is 15 percent less than the stock setup, while carbon monoxide output is nearly 75 percent less-and less than one-tenth of the allowable amount. Keep in mind that these are the standards for smog-choked California, which depending on a bike's displacement are 3 to 5.5 times more stringent than the national standards set by the Environmental Protection Agency.

Not only does the Yosh pipe surpass the strictest emissions standards in the country, it also meets Motorcyclist's criteria for a kickass exhaust: good looks, reduced weight, exhilarating sound and increased power. The R-77 is based on the system used on the Yoshimura Suzuki Superbikes, and that polished stainless canister looks damn fine on the Honda's right flank. Weighing in at 10.2 pounds, the slip-on is fully 3 lbs. lighter than the stock muffler. A larger-diameter bore lets out a little more of the CBR's roar, with a sweet, smooth note that's just loud enough to let you know it means business. Yoshimura wouldn't build it if it didn't make power, and back-to-back dyno runs showed a healthy improvement in midrange power, right where the street rider needs it. Horsepower was up about 5 bhp between 5000 and 6500 rpm and torque jumped 10 lb.-ft. within the same range.

Obeying the law never felt so good.

Yoshimura R-77 Slip-On
Price: $699.95
Contact: Yoshimura R&D

Verdict 5 stars out of 5
Way to lead the industry, Yosh! Now how about making 'em for a few more models?

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