A cable adjuster is a threaded barrel with a locknut, fitted where a control cable meets a lever, a carburettor top or the engine. Turning the barrel lengthens or shortens the outer casing of the cable, which changes the free play of the inner wire. Clutch, throttle, choke, front brake, speedometer drives and two-stroke oil pumps use them. Drum brakes often have a wing nut on the rod or cable at the wheel that does the same job.
What it does
It sets the free play in a cable so the control works fully without dragging. It also lets you balance two cables, as on twin carburettors.
Signs it is worn or failing
- Barrel seized in its thread, or locknut rusted solid.
- Stripped thread, so the barrel will not hold its setting.
- Split slot that lets the cable fall out.
- Adjuster wound right out to its end, showing the cable has stretched or the parts are worn.
When to replace it
Replace a seized, cracked or stripped adjuster. If it is at the end of its travel, replace the cable or check the worn part (clutch plates, brake shoes) instead of forcing the adjuster.
What to match when buying
- Thread size and length, and the cable end it takes. Many are part of the lever or cable.
- Locknut thread to match.
Fitting notes
- Clean and oil the thread before adjusting.
- Turn the slot away from the cable opening after adjusting, so the cable cannot pop out.
- Always tighten the locknut and recheck free play. See Adjust the clutch cable and Adjust the throttle cable.