Exhaust system Law in the United States and other countries to not have a catalytic converter. Converters may not be removed from a vehicle that is used only for "off-road" driving in the United States. The main purpose of a catalytic converter on an automobile is to reduce harmful emissions of hydrocarbons, carbon monoxide and nitrogen oxides into the atmosphere. They work by transforming the polluted exhaust components into water and carbon dioxide. Cat-back (also cat back and catback) refers to the portion of the exhaust system from the outlet of the catalytic converter to the final vent to open air. This
Four-stroke power valve system to develop such a system, called the Exhaust Ultimate Power Valve (EXUP). It first appeared on the Yamaha FZR EXUP and was later used on many other Yamahas. Later versions from Honda went by the names Honda Titanium Exhaust Valve (HTEV) and Honda Variable Intake/Exhaust (H-VIX), appearing on the CBR600RR and Honda CBR929RR. Suzuki's version is called Suzuki Exhaust Tuning (SET). The system is also used on the Triumph Daytona 675 triple. Four-stroke power valve system A four-stroke power valve is a device fitted to four-stroke engines that constantly adjusts the internal diameter of the exhaust system to better suit