How To Check and Adjust Your Motorcycle Throttle Cable

Setting your throttle free play is one of those simple adjustments that can make your bike feel more responsive and make it easier to ride smoothly.

Most motorcycle manufacturers recommend about 2 to 3 millimeters of throttle free play, but over time the cables will stretch and settle into their housings and you’ll end up with more slack. When that happens it gets harder to smoothly feed in throttle since there’s a delay between when you twist your wrist and when the carburetors or throttle bodies actually begin to open. Don’t worry, you can change the amount of throttle free play and set the slack to exactly how you like it in these six simple steps.

To check the free play, roll the throttle forward until it stops and take note of the position, then gently open the throttle until you feel the tension on the cable. The distance from the closed position to the tension point is your free play. There are seams on most grips that work well as a reference point so you can eyeball the movement, but, if you want to be really thorough you can cut out masking tape pointers and stick them on the grip and the throttle housing. Then turn the throttle and measure the distance.

If the free play is out of spec there are two places that the cable slack can be adjusted. There are usually inline barrel adjusters (sometimes one on both the opening and closing cable, but often only on the opening cable) and adjusters down at the carbs or throttle bodies. Ther barrel adjusters on the cables are for fine-tuning the free play, while the adjusters down by the engine are for making larger adjustments. The adjusters lengthen or shorten the cable housing, which effectively changes the length of the inner cable that’s doing the pulling.

For minor free-play adjustments, use the inline adjusters. Just slide the rubber cover off, loosen the locknut, and turn the barrel adjuster to achieve the desired free play. A dab of silicone lubricant will make reinstalling the boot easier.

Now, if setting the free play put either of the inline adjusters at the end of its range so it’s only holding on with a few threads, or if you can’t get the right free play using the inline adjusters, you’ll need to finagle the adjusters down in the engine bay. It’s the same basic procedure as working with inline adjusters, except the ones down by the engine are harder to access and a little more tedious to adjust.

Once you’ve set the slack, swing the steering from lock to lock and verify that the throttle doesn’t tighten up on you. Then start the bike and turn the bars lock to lock again and check that the idle doesn’t change. If it rises, check the cable routing to make sure it isn’t kinked or binding, and recheck and adjust the free play if needed. This is important!

If the idle rises, that could mean you don’t have enough free play, but it’s also worth checking the cable routing to make sure that it isn’t kinked or getting pinched. A happy throttle cable is a precise throttle cable and vice versa.