What Is a Yamaha Tors Control Unit?by Richard Rowe
The throttle override system used on Yamaha's all-terrain vehicles isn't specific to Yamaha; some variant of the system has found its way onto ATVs produced by almost every major manufacturer. While the TORS works admirably when new, years of dirt, mud and hard landings can turn the system into more of a liability than a safety feature.
TORS System Basics
TORS, or throttle override system, is a safety feature pioneered for use on high-speed Yamaha vehicles such as snowmobiles and ATVs, which use a pull-throttle cable system instead of a hard linkage. A TORS unit uses a throttle position sensor to check the position of the throttle on your handlebars; if the TORS unit detects a difference between the hand-throttle and the throttle cable position, it assumes that the cable's snapped. If this happens, the TORS unit cuts power to the ignition and kills the engine.
The TORS, often called the "brick," is a large aluminum unit bolted to the carburetor. There are two ways to find it: you can either follow the throttle cable from the hand-throttle to the back of the TORS unit, or you can follow the wires from the throttle position switch to the TORS' "black box" control unit. The wires from the black box go into your Yamaha's TORS control unit.
It's pretty fair to say that the TORS unit is universally hated by anyone with an older Yamaha ATV. The microswitch in the handlebars, the TORS control box, the TORS unit and all of the wiring in between offer numerous opportunities for failure. Computers and electronic control systems generally don't get along with the average ATV's operating conditions, which over time, make TORS failure almost inevitable.
Getting Rid of the TORS System
Many Yamaha enthusiasts and backyard mechanics opt to either get rid of or disable the TORS system rather than to fix it when it fails or run the risk of getting stranded in the middle of nowhere. There's two basic approaches: you can either disconnect and disable the TORS unit control box and reconnect the necessary wires, or you can install a TORS eliminator kit. If you have the money, a TORS eliminator kit is preferable because it not only eliminates the failure-prone "brick," it makes for a bit more room in the ATV's already cramped engine bay for easier carburetor adjustment. Of course, you'll lose out on the safety aspect of having a throttle override; but then again, walking home 13 miles through coyote-infested desert isn't particularly safe, either.
Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.