04 December 2019

Push-Pull motorcycle throttle cables. What's all that about then?

A push/pull throttle is a dual cable throttle operation where the pull cable opens the throttle plates, while the push cable, along with a throttle return spring, closes the throttle plates. The “push” cable is a misnomer as the push cable also pulls.

A push/pull throttle cable is an upgrade to the old standard single throttle cable linkage. The throttle grip works on the carburettors when twisting/throttling up and when releasing/throttling down. This is a step up to the single throttle cable type where only a spring is responsible for throttling down. With a push/pull throttle, should the spring fail, twisting the throttle will pull the throttle linkage back to idle.

In a crash, if the steering stops on a bike and is pushed in a bit from hard falls, the cable can often get caught between the frame and fork tube. This crushes the cable housing a bit, and the cable will bind. If a rock or something gets caught in the carb housing (if somehow the cover fell off) the spring won't close the carb slide. The second cable pulls the carb closed so it isn't stuck wide open. On a road race bike at 165mph+ approaching a tight turn with little run off area, riders want that peace of mind that if they close the gas, it will close. It is for this reason that it is now illegal in many countries to remove the push cable and rely on the spring to close the throttle.

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