Most manual transmission-equipped motorcycle’s make use of a clutch cable to activate the clutch system via the clutch lever. Very few, high-end motorcycles either make use of a hydraulic clutch, or an automatic clutch. That being said, a cable-actuated clutch is a setup which has stood the test of time as a reliable and easy-to-use mechanism for clutch operation.
Unfortunately, unlike its hydraulic and automatic counterparts, clutch cables can wear overtime and come out of optimal adjustment. This can result in partial disengagement of the clutch which, at the very least, could cause difficult shifting, and at the worst, lead to premature transmission wear and damage. This is why motorcycles equipped with a cable-actuated clutch often feature easy adjustability in order to make it easy for you to ensure that the tolerances are always up to spec. Having said all that, the purpose of this article is to walk you through the simple yet extremely important task of adjusting your clutch cable.
Before even getting started, the first thing you’re going to need to do is to give the clutch cable a nice and thorough once over on both the lever and clutch mechanism ends. This could require you to slide a rubber boot off of the ends in order to see the condition of the clutch cable. Once the clutch cable is visible, pull the lever in to get a good visual of the clutch cable.
If there are any breaks in the cable or housings, or if the steel cable has visible signs of rust, corrosion, or worse, has begun to fray, you’re going to need to replace your clutch cable. We highly advise against using a motorcycle with a frayed clutch cable, as this means that the cable has lost its structural integrity and can snap at any time. However, if your clutch cable looks perfectly fine and free of any corrosion or damage, you can now proceed to the next step.
How to adjust cable tension
Nearly all cable-actuated clutch systems come with adjustment barrels mounted on the clutch lever mechanism. But before you start loosening the adjustment barrel, take note of the slack currently present in your clutch lever. While the exact measurement may vary from motorcycle to motorcycle, you’re going to want to adjust the cable tension such that it has around 3 to 5 mm of slack.
Next comes actually adjusting the cable tension. This can be a little bit tricky, as tightening the barrel adjuster—turning it clockwise—will loosen the cable tension (i.e., increase the slack on the clutch cable). Conversely, loosening the barrel adjuster, or turning it counter-clockwise, increases cable tension (decreasing the slack on the clutch cable). Once you’ve set the cable tension to your desired setting, double check the cable free play with a vernier caliper or tape measure.
Lubricate the cable
Once you’ve finished adjusting the cable tension, you’re going to want to ensure that the clutch cable is well lubricated in order to prolong this wear item’s service life. Now, there are many ways to do this, one of which is to remove the clutch cable from your motorcycle. If you’re not up to the task, you could use the pointer straw which comes with most aerosol lubricants, and inject some lubricant in between the clutch cable housing and cable. You can then use a hair dryer or heat gun set to the lowest heat setting to warm the oil up a little bit to allow it to flow through the cable, thereby lubricating it in the process.
Some things to consider
When it comes to adjusting your clutch cable, tension is the name of the game. Having your clutch cable too tight and too loose has its own set of issues which could greatly reduce the service life of your motorcycle’s clutch and transmission. A clutch cable which is too tight may not enable the clutch to fully engage, which causes it to slip, thereby wearing away the friction material. On the other hand, a clutch cable which is too loose can cause the clutch to disengage only partially, which can really add unnecessary wear and tear on your transmission.