Clutch replacement is a pretty straightforward job, requiring only a few basic hand tools, the new clutch parts, and a couple hours. You even get an oil change out of it. It’s an easy DIY job, and there’s no need to take your bike to a shop or dealership if you feel that clutch a-slippin’.
After nearly 14,000 miles the factory clutch on my Z900 RS had started to slip. The bike had lost a lot of its muscular grunt when giving the throttle a twist, which makes up so much of the bike’s appeal.
First, before committing to the work of a full replacement, I wanted to make sure the clutch cable was adjusted correctly, as the slip could just be a poorly adjusted cable preventing the clutch from fully engaging. Of course, the cable was adjusted correctly, so that meant the clutch plates were worn out, and ready for a replacement.
First things first, you’ll need some new clutch components. There’s basically two approaches you can take here. You can either get the OEM (or aftermarket equivalent) plates and springs, or you can opt for an upgrade. The choice depends on how you want your clutch to feel, and how long you want it to last.
I’m going for an upgrade, and dropping in some Kevlar friction plates and some stiffer springs courtesy of Barnett. The factory steel drive plates were in great shape, so I opted to reuse those. After ordering the new friction plates and springs, I was ready to go.
Time to get out to the garage to knock this one out. Let’s rock and roll.
What you’ll need:
- Combination wrenches.
- Socket wrench and/or t-handle driver.
- Clutch plates.
- Clutch springs. Generally, if the friction or pressure plates are worn out, the springs should be replaced as well.
- New clutch cover gasket (or go full DIY and use some RTV silicon gasket maker)
- Oil (however much your bike needs for an oil change + some extra for soaking the friction plates)
- Shop towels, brake cleaner, and nitrile gloves to keep things clean.
- A cardboard box to put under your bike to catch any oil drips.
- A couple hours.
I’m performing this job on my 2018 Kawasaki Z900 RS, and while every bike has a few nuances of its own, the general process is going to be pretty similar for most Japanese motorcycles with a cable-operated wet clutch.
Put the new friction plates in some oil to soak while you prep everything else and disassemble things. The friction material needs to be coated in and absorb some oil. Some people will recommend soaking them in oil overnight. That shouldn’t be necessary, but won’t hurt anything.
The hour or so it takes to get everything else set up and disassembled should be enough. This is a good time to use up that leftover half quart of oil you have from your last oil change. For soaking, I just clean out an oil drain pan lay the plates out in it, and pour the oil on them like I’m dressing a salad made of Kevlar and steel.
Put something under your bike to catch any oil drips or spills. If you’re fancy and have oil absorbing mats, you can use those. If you order a lot of stuff from Amazon like, oh, pretty much everyone, use a couple cardboard boxes.
Next, drain the engine oil. Behind the clutch cover is most of the bike’s oil (guess that explains why the oil sight glass is located there), and it’ll come dumping out if you open it while it’s still full. You could do it that way, if you need some practice cleaning oil off your garage floor. Some people might even suggest to “just lay the bike on its side,” but that’s the sort of thing that gauche people who leave their cell phone on at the movies do. Oil isn’t expensive, and you’re going to want those new clutch plates swimming in fresh oil, anyway.
If the clutch cable is attached to the clutch cover, you’ll need to remove it. If it’s not attached, you can skip this step. You need as much slack as possible in the cable to remove it. Loosen it first at the clutch lever, then at the bottom near the engine, where it connects to the release arm.
Once it has as much slack as Pauly Shore character, remove it from the clutch release arm. This may require some fiddling with the clutch release arm, sliding it up out of where it sits within the clutch cover, or removing the spring on the arm so it can move more freely.
Now remove the clutch cover. I like to take my time here, loosening the bolts a bit at a time, in a criss-cross pattern. I prefer using a t-handle for this, since it’s easy to gauge 1/4, 1/2, or full turns of the bolt as I go, to keep things nice and even.
When removing the clutch cover bolts, note whether or not any of them are of different lengths. If any of them are, mark the holes and their corresponding bolts with a grease pencil or nail polish so you can match them up later.
With the clutch cable and cover bolts out of the way, carefully remove the clutch cover. There will be a bit of oil left in it, so have some towels on hand to clean it up. If you’re lucky like me, the gasket will peel off cleanly and in one piece with the cover. That’s great, because you can reuse it. If the gasket sticks or comes apart in pieces, you’ll need to clean the gasket off the surfaces, and purchase either a new OEM gasket, or use some RTV gasket maker when you put it back together.
Slowly loosen the pressure plate bolts. The pressure plate is pressing against the clutch springs, and the whole thing is under quite a bit of pressure. Maintaining even pressure distribution is important here, so use a criss-cross pattern like before, and loosen them slowly, 1/4 to 1/2 a turn at a time.
Once the bolts are loose, remove the pressure plate and springs. Keep track of any spacers that were in place, and the order they go in, so they can go back together in the correct sequence during reassembly.
Now comes the party. Start removing clutch plates one at a time, placing them aside in the same order that you removed them from the basket and hub assembly. You should end up with a stack of plates with the first plate you removed face down on the bottom and the last plate on top.
With everything disassembled, take a moment to inspect the basket, hub, and other components of the assembly to check for unusual wear, damage, and so forth. Assuming everything is in good working order (as it was in my case), I like to take this opportunity to clean up the basket and hub. There’s going to be some gunky clutch material and oil clinging to the sides of the hub and basket from the old clutch wearing down.
Give a towel a spray with some brake cleaner, and wipe things down a bit. Be careful, use something durable and lint free; you don’t want bits of towel or lint in your engine, and don’t spray brake cleaner directly into the clutch hub. It probably wouldn’t do anything, but there’s no need to tempt the motorcycle gods and their wrath.
Cool. Nice and clean.
Time to put things back together. Start placing the plates back into the clutch in reverse order. If there’s a spring plate, even if you’re replacing the steel plates, you’ll more than likely reuse it, unless it was somehow damaged and you ordered a new one; it’s not a typical part of a clutch pack replacement. Simply replace the old friction and/or steel plates with the new ones as you go.
The clutch is going to be assembled by alternating between friction and steel plates. During the reassembly process, I keep a towel and brake cleaner handy, so I can spray the towel down and wipe the steel plates clean of any old clutch material, glazing, or other gunk that may be stuck to them.
Once all the plates are in, put the springs in place on the hub, put the pressure plate in place, and start bolting it down. In some cases, you may have to press against the pressure plate in order to compress the springs enough for the bolt’s threads to catch.
Like during removal, gradually tighten the pressure plate bolts down in a criss-cross pattern, in order to maintain even pressure on the springs. Tighten the bolts down to their required torque specs. I like to live dangerously, and use German torque settings; gutentight.
Now, put the clutch cover back in place. Fit the indexing notch in the release arm over the tip of the hub pull rod. This can be tricky on some bikes. Some are silly and those two parts are precisely to fit together in a very specific way. The Z900 RS is fortunately, not such a bike, and simply rotating the release arm into place over the pull rod sets it into place.
Bolt the cover back down; like during removal, I like using a criss-cross pattern, and tightening the bolts by 1/2 to 1 turn with each pass, to keep pressure nice and even. Take your time. It’ll take longer, but that beats damaging something.
Reconnect the clutch cable to the release arm. Now it’s time to get the clutch adjusted. This is a bit of an art form, but is not as hard as it seems. No ritual sacrifices necessary…usually. It’s basically a three step process.
- Start at the lever, and set the adjuster there to the halfway point.
- Move to the adjuster nuts at the clutch release, and adjust those until the free play at the lever has been taken out.
- Head back up to the lever and fine tune the adjustment until the free play at the lever is at the specified amount.
For the Z900 RS, free play is specified at 2-3 mm.
One trick for measuring free play is to use an Allen wrench that falls within the free play measurement like a feeler gauge. In the case of my Z900RS, I use a 2.5mm wrench, since it’s right in between the 2-3mm free play specified. Gently pull the lever just until you feel the slightest resistance. If the Allen wrench slides into the space with a small amount of resistance, then it’s good.
Another method for measuring free play is to mark a piece of masking tape with three index marks. One for the zero, or starting point, one for the minimum free play (2mm for the RS), and one for the maximum (3mm for the RS). Attach it to the top of the clutch lever assembly (make sure it’s attached to a part that doesn’t move) so the zero mark is aligned with the edge of the lever in the fully closed position. As above, pull the lever just until you feel the slightest resistance. If the edge of the lever is within the index marks, then your free play is set correctly.
Home stretch, now. If you used RTV to replace the cover gasket, you’ll need to give it time to cure overnight before proceeding.
Refill your two-wheeled best friend with some fresh oil, start it up, and take it for a test ride. Make sure everything is working correctly, and check for any leaks at the clutch cover gasket. If everything checks out, congrats. You’re done.
TLDR; how to replace a motorcycle clutch
- Place the new clutch plates in a bath of clean engine oil to soak for a few hours, or overnight.
- Drain the engine of oil.
- Loosen the clutch cable and remove it from the clutch release arm.
- Remove the bolts from the clutch cover and remove it.
- Scrape off excess gasket material from the clutch cover and engine if the gasket is no longer serviceable.
- Loosen and remove the clutch pressure plate bolts.
- Remove the pressure plate and clutch springs.
- Remove the clutch plates from the clutch basket.
- Inspect the basket and clutch hub for unusual damage or wear.
- Clean the clutch hub and basket of old clutch material, oil, and debris.
- Install the new clutch plates. Installation sequence is reverse of removal.
- Reinstall the clutch springs and pressure plate. Tighten pressure plate bolts to spec.
- Line up the hub pull rod with its receiver on the release arm inside the clutch cover, and reinstall clutch cover (replacing gasket with new OEM or RTV silicone if needed). Tighten cover bolts to spec.
- Reconnect the clutch cable to the release arm and adjust the clutch to the specified free play as indicated in your motorcycle’s manual.
- Put new oil in the engine, fire up the motorcycle, and take your motorcycle and it’s fresh clutch for a nice long ride.
