How to adjust a motorcycle clutch on a Harley Big Twin

Aug 08, 2017

Time marches on, and so too does the wear on your motorcycle clutch.

Whether you are coming up on a factory service interval or are have a feeling that something is just a bit off as you work through your gears, the process of adjusting your clutch is a relatively simple endeavor. Regardless of your reason for diving in, the steps listed below will help you navigate the waters when adjusting the clutch on your Harley-Davidson Big Twin.

NOTE: Our example motorcycle is a 2014 Harley-Davidson Low Rider, but the process is going to be the same for whatever model of Big Twin you pilot.

Step 1: Remove the clutch cable cover

Designed to protect the clutch adjuster mechanism from dirt, water, and particularly juicy airborne arthropods, the clutch cable cover (or “boot”) is the accordion-looking piece of rubber that resides about half way between your handlebars and the bottom of your Big Twin frame. For most Harleys that have a cable clutch, you will need to adjust the clutch cable prior to getting to work on the clutch itself. As noted, the cable clutch cover isn’t difficult to find, and once you do, all you will need to do is simply slide it up or down to reveal the clutch cable adjuster mechanism that takes shelter underneath.

Removing the cable clutch cover
You wouldn’t want to face the elements bare-ass naked, and neither does your clutch adjuster mechanism. Hence, the accordion-looking clutch cable adjuster cover. RevZilla photo.

Step 2: Adjust the clutch cable (Part 1)

With the clutch cable cover out of the way, you will need to add slack into the cable. Doing this is essential to ensuring that the cable has no affect on the clutch as it is being adjusted later on. By adding slack into the clutch cable, what you are actually doing is collapsing the cable housing that the cable pushes against. In doing so, you are removing any tension, and when complete you should be able to squeeze the clutch lever all the way without any resistance.

To add slack into the clutch cable, you will first want to take a wrench and lock onto the adjuster itself. In our example, that wrench is a 1/2 inch. With the wrench secured to the cable clutch adjuster, use another wrench to loosen up the jam nut that is secured directly to the top of the clutch adjuster. The jam nut is used to hold the adjuster in place, so in order to proceed, you will need to dial the jam nut all the way back creating room for the cable adjuster to be dialed back as well. Be sure to take the clutch cable adjuster all the way to the point that it bottoms out, thus releasing all tension on the clutch cable.

Loosening a motorcycle clutch cable
Before you can adjust slack into the clutch cable, you have to first roll back the jam nut that holds it in place. RevZilla photo.

Step 3: Remove the clutch cover (aka the derby cover)

Think of the derby cover as Steve Rodgers’ trusty shield. While there is no doubt that it looks fantastic when well polished, it is a purpose-driven piece of equipment that has one purpose above all others: to provide you with an easy access point to do this very job. While Agent Orange and others had plenty of trouble separating Captain America from his shield, you should have no problem removing the derby cover from your motorcycle.

To remove the derby cover, your job should not require much more than unscrewing a handful of bolts holding it in place. That being said, there are a few things that you should keep in mind as you go.

Removing a motorcycle clutch cover
Keep pressure on the derby cover when removing the last screw. Otherwise, it is likely to fall off. RevZilla photo.

Protip 1: If your bike is sitting on a jiffy stand, it is possible (though not probable) that, due to the angle, some of the primary fluid could leak out if it is overfilled. It is always a good idea to place a rag underneath your motorcycle to guard against gunking up any surfaces that you don’t want to gunk up.

Protip 2: Keep your hand on the clutch cover to support it as you remove the final bolt. More than one rider has had to learn the hard way that derby covers have a propensity for succumbing to gravity immediately after that final bolt is removed.

Step 4: Loosen the jam nut on the clutch adjuster

NOTE: In this step we are going to be talking about the clutch adjuster, which should not be confused with the clutch cable adjuster mentioned earlier. 

Like the clutch cable adjuster, the actual clutch adjuster also uses a jam nut to keep everything in place. To break this free, you will want to use a wrench for the nut itself (in our case an 11/16) as well as a hex key to hold the clutch adjuster in place as you do. It's entirely possible that your motorcycle will need a screwdriver rather than an Allen key. For simplicity's sake (and to eliminate a multitude of text in parentheses) whenever we mention an Allen key in this guide, just replace that with "screwdriver" if your motorcycle necessitates the latter. Regardless of what tool you will use, before moving on to Step 5, where you will actually adjust the clutch, you need to be sure to loosen the jam nut all the way out.

Loosening the jam nut on a clutch adjuster
Use a combination of your Allen key and wrench to loosen the jam nut on your clutch adjuster. RevZilla photo.

Step 5: Adjust the clutch

At this point, you are ready to adjust the clutch. Using your fingers, tighten the clutch adjuster until it bottoms out. Do not torque it. Do not pinch harder and try to be sure it is really snug. When it bottoms out, stop. End of story. You have reached the desired destination.

Tightening a motorcycle clutch adjuster
Your fingers are the right tool for snugging down the clutch adjuster. RevZilla photo.

With the clutch adjuster bottomed out, insert your Allen key. As always, you definitely will want to check your factory service manual here for specifics, and when you do, it will likely give you a set point (1/2 turn) or a range (1/2 to 3/4 turn). The range of a turn can vary in search of a specific feel, however, as the wear level of parts and personal preferences all come into play. For our example, a general rule of thumb for four-, five-, and six-speed setups is to turn back the Allen key (counterclockwise) one half turn. So, if you insert your Allen key and it is pointing to six o’clock, you will pull your best Dr. Emmitt Brown and wind it back in time to 12 o’clock.

Turning a motorcycle clutch adjuster
A half turn back from the "bottomed out" position on your clutch adjuster is a standard best practice on many Harley Big Twins. RevZilla photo.

Once you have made the turn, run the jam nut back down by hand to tighten things back up. As you do this, be sure you keep the Allen key in position to hold the clutch adjuster steady. If you don't, it's likely you will inadvertently twist it out of the desired position. Finalize the step by using the wrench to fully tighten the jam nut. As with the rest of this process, do not over-torque.

Tightening a clutch adjuster jam nut
With the clutch adjusted, snug down the jam nut with your screwdriver. RevZilla photo.

Step 6: Put the derby cover back on

With the fight against clutch malfeasance won, it’s time to shield back up and reattach the clutch cover. When doing this on your Harley Big Twin, it is a pretty simple process.

Always start this process with your fingers to get the bolts going. In addition to being easier and more efficient, it eliminates the chance that you will tighten down any individual bolt too soon. With all of the bolts in place use your screwdriver / torque wrench to put the finishing touches on things. Keep in mind that the order in which you do this can make a difference. At this stage, you will want to tighten down bolts that are opposite each other (as opposed to just doing them in order around the cover). Much the same as tightening the lug nuts on your car tires, working in this pattern helps to ensure that the cover evenly draws down against the seal.

Tightening a motorcycle derby cover
When reattaching the clutch cover, it is important to tighten the screws in a star pattern (like you would with lug nuts). RevZilla photo.

NOTE: As a rule, you will always want to replace gaskets when breaking the seal on parts. Gaskets are cheap, so it’s well worth springing for new ones. That being said, when it comes to the gasket on your derby cover, they can often be reused (depending on condition). If you do replace, it is likely that an aftermarket option like James Gaskets will look slightly different than the factory gasket from Harley. Not to worry, they do the same thing.

Motorcycle clutch cover gaskets
Some aftermarket gaskets will look different than their from-the-factory counterparts. Worry not, they do the same thing. RevZilla photo.

Step 7: Adjust the clutch cable (Part 2)

For this step in adjusting your motorcycle clutch, you will simply need to repeat Step 2 in reverse. If you squeezed your clutch lever to test the reduction of tension in Step 2, you will begin to see it creep back to its original position now. Do not fret, this is not the work of an invisible ghost of wild rides since past, it is merely the effect of tension returning to the clutch cable.

Motorcycle Clutch Lever Movement
As you add tension back to the clutch cable, the clutch lever should return to its original position on its own. RevZilla photo.

To check your progress, you can simply keep tabs on the play in the clutch lever as you go. Refer to your factory service manual, but typically, somewhere in the range of 1/16 inch is a good amount of free play. When you get the tension where you want it, re-tighten the jam nut to the clutch cable adjuster.

Tightening the clutch cable jam nut
Re-snugging the jam nut to the clutch cable adjuster ensures you will keep the desired level of tension. RevZilla photo.

Step 8: Move the clutch cable cover back down

OK, OK. You're done(ish). While the excitement to get back to thundering down highways and intimidating those with lesser roars (like lions, dinosaurs, and fire-breathing mythical winged beasts) can be immense, don't forget to pull the cable clutch cover back into place before you do.

Protip 3: As these pieces of rubber get older, they tend to get bit grabby. Hit the base with a shot of silicone to make this process smoother.

Adding silicone to motorcycle clutch cable cover
A quick blast of silicone under the clutch cable adjuster cover makes it way easier to slide back into position. RevZilla photo.

Conclusion

Adjusting the clutch on your Harley Big Twin is a relatively simple task that can help you dial in the feel that you like while saving you a few bucks by not necessitating that you hand over your bike to the shop every time you need to make a few tweaks. In the end, this process takes less time than ordering the pizza you will want to sit down and enjoy afterwards. So get the hand tools out, the silicone spray on the ready, and plan accordingly for that delivery of cheese and pepperoni goodness.

Oh yeah, and if you have any questions, don’t hesitate to give our Gear Geeks a shout! We are here to help.