Ghost says, “Let’s learn about Clutches”

Not going anywhere? Cant stop going?

What does the clutch do?
Ah, the clutch. Such a complex collection of very simple mechanics. First, lets understand what a clutch does. To do this, Ghost needs to make a few general statements about engine operation. Most engines are operated by the explosion of gas, air and spark in the valve chamber. This sequence throws your pistons back, and makes your camshaft turn. (again Most engines, VTEC is a little different but operates on same basic principals) The camshaft is connected to the gear shaft. Attached to the gear shaft is a basket of plates called the clutch basket. Connected to this basket via a series of gears to simply transmit the motion, is the main drive, which turns your sprocket and chain. The clutch basket comprises of some slip plates and some grip plates. As long as the bike is in any gear other than Neutral, the basket is in constant pressure against the gear shaft and drive shaft by some springs.

Ya, ok we get it, but what does the clutch do?!
Ok now to the point, when a rider pulls in the clutch, you essentially put force against the clutch plates, and open them up, thus disconnecting the link between drive and gear.

Sounds too simple right? (course it is)

How can you tell if your clutch is bad?
Below Ghost has outlined some basics for troubleshooting a motorcycle clutch system. This is fairly general. Different bike manufacturers tend to use slightly different methods of delivery, however the fundamentals are all the same. If your clutch isn’t working properly, (and im sure you already noticed it), as described above, there is a disconnect of some type in the system.


Ok, here’s a hit list for you to check out. Starting with the simple easy stuff.

Get a second opinion. (find someone who rides a lot, and let them take it for a “round the neighborhood” trip. )

Adjust the thumb wheel at the left hand lever, and move the lever out. (this gives you more stroke, and a longer reach to compress the springs in the clutch basket)

Double check all your bolts. (ensure all the bolts in the Secondary cylinder are secure… don’t over tighten.)

Bleed the system. (do not underestimate this; it take a long time to get that stubborn little stupid dam bubble out) ((This includes cracking some of the banjo bolts. At times, if a bike is left to sit for a long while, and it has an air bubble, it could rise to the top, and be in your banjo bolt at the master cylinder))

Replace the fluids and bleed the system. (Dot 4 only.)

Replace the seals in the Master cylinder piston. (old bike, sits a while, seals get a set in them, then you go and move the lever a few times, and ruin the seal. It happens)

Replace the seals in the Secondary cylinder. (same as the Master cylinder, but doing this one sucks hairy ones, cause the inner seal and piston must be set perfectly, and then the outer seal must be set. ***WARNING*** the outer rubber is NOT, repeat NOT, a cover boot as you may think, it is an actual seal. When pulling this cylinder, ensure you keep it depressed in, and do not let the piston come out of the cylinder wall. You will curse yourself for hours if you do.)

**SPECIAL NOTE HERE: if you replace the seals in your secondary cylinder, do it, submerged in DOT 4 fluid. the fluid is clear, so you can see what you are doing...and this eliminates the variable that you will put more air in.**

Check for excessive deflection / add support if necessary. (If you sit down at your bikes side, and repeatedly pull the lever, you should be able to watch to see if your Secondary cylinder flexes and deflects excessively. Some of the main sprocket guards are weak, or cracked, and provide no rigidity to which the cylinder will force against. If this is your problem, let me know I will show you how to properly re-support this area permanently.)

Pull your clutch rod. (check the rod for damage or that its broken in two…hey it happens)

Remove the right side engine cover, and inspect the clutch springs. (sometimes the springs can get broken, and broken springs like to nest within itself…which causes a high resistance force.

Pull the clutch basket and check for wear. Plates that are burnt up tend to look glossy and can even be warped visually. The grip plates may also appear to be baked with a crust on the outer edges if the engine got too hot, or the clutch was always engaged. This excessive heat will cook oil. Its nasty. This means your previous setup and stroke further forward in the system was never correct…or that you ride with the clutch partially in a lot. If you do, stop it. (get a micrometer, and measure the overall thickness of each clutch plate, and clutch slip plate. Cross with your bike repair guide and determine if you need to replace your clutch disks… **more common on bikes with 60K + miles on them**, then again, if the system wasn’t right from day one, you could ride the clutch so that it burns them down rather quickly too)

At this point, if your clutch still isn’t functioning properly, your issue could be within your individual gear levers and the gear cam. (I recommend you take the bike to a professional for a good run down inspection of your work, before you begin to open and work on the transmission assembly)



That’s a lot of info Ghost, can you make this even simpler for us VFR’s?

Sure thing.
Your left lever pushes a small piston in your master cylinder. That cylinder pushes fluid to the secondary cylinder. The secondary cylinder pushes on your clutch rod. The clutch rod pushes on the clutch basket, and separates the plates.

What can you do to prevent problems and keep the clutch system running good?

Proper preventative maintenance. Inspect your hoses. Look for leaks. Replace your clutch fluid about every 10,000 miles. (yes, I know it sounds like its too often.) If the bike ever runs too hot, fix the problem, then do an oil change immediately. Make sure your clutch isn’t partially engaged. Don’t ride the clutch. Have a seal kit ready, for when you need to replace them. (for some $4.00 USD seals, wouldn’t you rather have some on hand than to wait 2 days to get them…and not be riding??)

How do you ensure the clutch isn’t partially engaged?

Your clutch should always be set so that when you pull in the lever, it engages early, and lets out early… (I.e. as soon as you begin to let the lever back out, you should begin to feel the bike try to roll.)

One last note. If you ever drop your bike, left side or right, replace your clutch fluids, and do a thorough inspection; every seal, every wiper seal, every mechanical linkage. The last thing you want to do after dropping a bike, and getting back on it, is to find out late that you can’t get out of gear, or can’t get into one.

Keep your fluids clean and inside their systems. Love your clutch.
Ghost out.