FAQ: Wet v. Dry Clutch

Monsters either come with a wet clutch or a dry clutch. Not sure what that means? Read on . . .

What is the difference between a wet clutch and a dry clutch?

Wet clutch. A wet clutch is sealed from the outside and the clutch plates are bathed in oil. Hence, it’s a “wet” clutch. Almost all bikes—including pretty much all Japanese brands—have wet clutches.

Dry clutch. A dry clutch does not have any oil in it or between the clutch plates. If you take off the cover to a dry clutch, you can see the clutch spinning around. They make a loud clacking sound that grows louder and louder as the clutch wears. Dry clutches are a signature of Ducati bikes, though not all Ducatis have them. In fact, the DMF logo is made to look like a dry clutch. There are some non-Ducatis out there with dry clutches as well, but you’re unlikely to come across them. Here's Juan's:

What are the pros/cons of a dry and a wet clutch?

A wet clutch requires less maintenance, is quiet, and has an easier pull and less bite on engagement. In fact, the APTC slipper clutch (a special kind of wet clutch) on the 620, 695 and s2r 800 significantly reduces the effort to engage in the clutch even when compared to a standard wet clutch. The downsides to a wet clutch? No cool Ducati dry clutch rattle. And it’s harder to change out clutch plates.

Dry clutches come from the racetrack, where people need to switch out clutches often. They’re easier to change out, and are much louder as the plates smack against one another with no liquid between them. As the clutches grow older, they'll get louder and louder. In some cases they grow so loud that they compete with aftermarket exhausts as a noise source. Many Ducati enthusiasts love the sound of a dry clutch, though they often lead bystanders to ask whether the bike is broken. With a dry clutch, you can also run and open clutch cover (or no clutch cover) which allows people to see the clutch in action. Folks often add blingy pressure plates so that you can watch the shuny bits spin and rattle. A dry clutch requires more maintenance, can be (too) loud, and is often hand cramping in traffic. Many people remedy the hand cramping by adding an aftermarket slave cylinder. Dry clutches also grab more upon engagement.

What is the difference between an open clutch and a dry clutch?

An open clutch is a dry clutch where someone has partially or completely taken off the clutch cover, or changed out the clutch cover, leaving the clutch exposed. Here are some examples.

How can I tell if my bike has a wet clutch?

You can look at the cover on the right side. If there are bolts (5 of ‘em) that allow you take off the cover, it’s a dry clutch. If not (you’ll see 4 bolts), it’s a wet clutch.
You can hear the difference as well. They sound very different. A dry clutch clacks. A wet clutch does not.
You can also tell by the model. The smaller displacement monsters have wet clutches and the larger displacement monsters have dry clutches.
Wet clutch models: 400 (Japan), 600, 620, 695, 696, 750, 800 and S2R.
Dry clutch models: 900, 1000DS, s2r1000, 1100, s4, S4r, S4rs, S4rt

Can I keep my stock cover but make my dry clutch louder?

Sure. You can take off the clutch cover and the rubber gasket. Then put some washers between the cover and the engine case and reinstall the clutch cover. It’ll let some of the dry clutch sound out, but will look almost the same as it did before.

Can I make my dry clutch quieter?

Yes, but I'm not going to tell you how. That's blasphemy. <grumble> Fine, ok, I'll tell ya. Here's one option.

Is a dry clutch the same as a slipper clutch?

No. They're completely different animals. A slipper clutch allows the clutch to slip if you bang a hard downshift. It prevents rear wheel lock-up. But slipper clutches don't have anything to do with whether the clutch is wet or dry. Slipper clutches are common in racing and cost $$$ if you install an aftermarket one. Some bikes come stock with them, others don't. (the APTC "slipper" in some 620s, the 695 and the s2r 800 is sort of a slipper clutch, but that's a different story).

What are my cosmetic options if my Ducati has a wet clutch?

You can paint the clutch cover or install a clear window or find some other cool mod that doesn't involve drilling a hole in your clutch cover and letting all the oil out. A lot of folks ask if it is possible to convert a wet clutch to a dry clutch. The short answer is that it is possible (a few have done it), but it’s not cost effective. For the price, you can often upgrade to a larger displacement engine or bike that comes with a dry clutch. There's another, more labor-intensive way of getting that dry clutch sound, as shown in the video below. laughingdp

ducati 848

Is dirt/water/rain a problem for an open dry clutch?

Not really. The clutch spins fast enough and gets hot enough when the bike is running that dirt and water are not really an issue. Most folks will tell you that they run an open clutch in the rain with no problems whatsoever. The one place I've personally had problems is washing the bike. You have to be sure to start it up afterward to blow out the water so that your wet clutch plates don't stick together when you start it up the next day. If they do, it's no problem. It just takes a moment for them to break free of one another. (Tip: If you've just washed your bike, watch out for clutch spray. Hold a rag near--but not over--the clutch when you start it up. Otherwise, your freshly washed bike will get sprayed by all the muck still inside the clutch). Also, the stock springs will rust eventually with an open dry clutch. You can replace them with stainless springs and resolve the problem.