wet vs dry clutch...?

[M-Oorb]

Ok so I have a little( probably long ) story to tell before I get to my actually question. So if you would like just skip to the end for the question.

So today after work I went motorcycle shopping with 2 of my friends(shopping for them). They are both non riders but would like to get into it...especially after hearing me talk about mine all day and see me on this forum allll the time. So there was a set of motorcycle dealerships by my work that we went to go stop by. The first one was the Kawasaki dealership. I basically asked both of my friends what they were looking for in a bike and they said basically something fun and sporty but not something they would die on. They said they both did their research and really liked the 250 and the things they have heard me say about it. So right from the get go I was very impressed and glad they didn't say they wanted to start with a 600. They are both pretty level guys and they take their wild driving out on their safer cages (one drives a turbo scion tc and the other a mazdaspeed 6) So anyways...we got to the dealer and they loved the bike right away. But i wanna say the sales people sucked! I knew more stats and info about he 250 and also the 650 R that they were looking at....prices, hp, all the basic stuff any decent sales person should know. I was veryyyyy disapointed Then we went over to check out the Honda dealership because they also sell those hyosung 250's. Ive read reviews about thier lack of quality but they wanted to check them our anyways. Well the bikes looked pretty decent but quality was def. lacking and the way you sat on the bike...not nearly as comfortable as our little 250s. Again....sales people sucked...did'nt know a thing about those or the CBR's(I figured id look while was there ) So we decided to go next door...Ducati dealership . Now i must say I have never really looked hard at one in person but those are some sexy bikes. The way they look and sound...molto bene. The carbon fiber pieces looked a little cheap but I whateverr. BUt the sales lady who came over to talk to us...and offer me a test ride ..really knew her stuff. You could tell she didn't just see this as a job...it was a passion. I wish all sales people were like that.

But anyywaayyss I digress. My question. On the ducati's she was telling me about how they have a dry clutch system. It was really cool cause one of the bikes had a lexan cover over the clutch so you could see the inner workings. She said how the dry clutch made a certain noise that people mistake for someting being wrong but thats part of the charm of the bike. I thought an odd noise would be a draw back but I guess its like our gas tank whistle...gotta have it to appreciate it

Ok so I' serious..now the question. What is the difference in the way a dry clutch, such as on the ducati's, and a wet clutch...as on our bikes, work? What is the main functioning difference and draw backs and advantages of each. Thanks and sorry for the long story

[komohana]

short reply to a long question

a dry clutch is as it's name implies as opposed to a wet clutch that has it's plates immersed or sprayed in fluid (oil) for lubrication and cooling. wet clutches are said to perform smoother, and last longer, although you'll read that a wet clutch looses 'energy' to the fluid that cools and lubes it.

i've read that dry clutches are easier to maintain. wet clutches can be prone to slippage with the wrong oil. dry clutches are prefered to wet on the track for the power savings of not having a clutch spinning in oil. small savings, but power had nonetheless, and for a host of other reasons like oil contaminates etc.

i think both function well and it comes down to what ya riding and where you're doing your riding at. for the street i'll keep my wet clutch thank you very much!

[M-Oorb]

Haha well what can I say...it was an interesting day and I wanted to share. I thought thats the way it would be...names pretty intuitive. So basically the draw backs and advantages would pretty much be the same as say an automatic and stick. Auto is usually smoother but you lose some power due to the ATF and a manual has direct power and thus not as smooth? I know an automatic isnt like a wet clutch haha but you get what im tryin to say right?

[komohana]

Originally Posted by M-Oorb

I know an automatic isnt like a dry clutch haha but you get what im tryin to say right?

OF COURSE we do!

[M-Oorb]

I need to learn to keep my mouth closed :x...or I guess keep my hands busy doing something else instead of typing...like this

Sorry I just really liked that one

[komohana]

its all good bruddah matt

[Alex]

There are almost zero practical advantages to a dry clutch on the street. For that matter, there aren't really any disadvantages either. Performance wise it's pretty much a wash. It's just a choice. They are preferred in racing not primarily due to less friction spinning in oil, but because a dry clutch can be changed out in seconds in the pits without affecting the oil supply in the blazing hot motor.

Many Ducatis still come with a dry clutch as it remains a trademark of that brand. They are supposed to rattle like that; that sound is a trademark of a Ducati Superbike. Some of their newer bikes though, including the 848, both new Monsters, and a few other models are now coming with wet clutches.

[M-Oorb]

Alex, you are just a wealth of information

[Apex]

Keep in mind that the oil cools the wet clutch. So that means the chances of you frying a clutch is not very easy on a wet clutch system.

Go to the Ducati's. They have the dry clutch system. Nice since you do not have to drain any oil out to change them. However they can overheat quite easily. There is nothing there to cool them. So it operates like a manual transmission in a car. If a person wants to "feather" the clutch, it can overheat very quickly. Overheat the clutch, and it will gloss over. Do it too much and you just lost your clutch. You take care of it and work it properly, it will last for quite a while with no issues.

[Alex]

Mark,

Your points are valid, but modern dry clutches aren't as finicky and fragile as they once were. All BMW boxer motors (including my RT) still come with dry clutches, and you can abuse the crap out of that thing and it'll still last 50k miles. Almost all automobiles use a dry clutch system, and even on the most race-ready Ducs with a light dry clutch assembly, the only way you're going to overheat it is with repeated drag-race starts over and over again, and even if you do, letting them cool often returns them to perfectly workable condition; it doesn't necessarily render them useless and requiring replacement.

[Apex]

Originally Posted by Alex

Mark,

Your points are valid, but modern dry clutches aren't as finicky and fragile as they once were. All BMW boxer motors (including my RT) still come with dry clutches, and you can abuse the crap out of that thing and it'll still last 50k miles. Almost all automobiles use a dry clutch system, and even on the most race-ready Ducs with a light dry clutch assembly, the only way you're going to overheat it is with repeated drag-race starts over and over again, and even if you do, letting them cool often returns them to perfectly workable condition; it doesn't necessarily render them useless and requiring replacement.

I used to do a lot of drag racing. I'm used to seeing clutches die brutal deaths.

[Alex]

Agreed. Drag racing means keeping a budget for clutch replacement, no way around it.. At the top level of motorcycle drag racing (as well as most of the car classes), AFAIK they are changing out the clutch every single run.

[Bill N]

On another forum it was advised that almost all dry clutches will not survive more than approx 100,000 miles. That has proved true for me as mine failed at 95,000 miles of street riding. Not bad tho and I'm planning on getting 100K out of the replacement clutch.
Bill

[M-Oorb]

On what bike Bill? 95k sounds like a good amount of distance on one bike...hope my ninja lasts that long

[Alex]

Originally Posted by Bill N

... almost all dry motorcycle clutches will not survive more than approx 100,000 miles.

Fixed. Most folks will have to replace the clutch plates and springs of just about any motorcycle clutch at least once by 100K miles, whether a wet or dry design.

[Bill N]

Originally Posted by M-Oorb

On what bike Bill? 95k sounds like a good amount of distance on one bike...hope my ninja lasts that long

It's a 1998 Moto Guzzi 1100. My riding buddy with a 1000 Guzzi sport replaced his dry clutch right at 100,000 miles. Alex wrote and is likely correct that just about all motorcycle clutches need attention/replacement by 100K. The little Ninjette with humble torque might have a clutch that will last for a long long time if not abused.
I plan to ride the Guzzi for another 100K.
Cheers, Bill

[kkim]

Originally Posted by Bill N

The little Ninjette with humble torque might have a clutch that will last for a long long time if not abused.

lol.. if only the engines would make it to 100k.

[M-Oorb]

Well even at the rate I'm riding my bike...should still last me about 40 years

[HKr1]

Another reason for the dry clutch, when it wears... the friction material is kept outta the crankcase, and thus outta the oil system/filter.

[CC Cowboy]

Dry-Clutch. I've had them on my Suzuki 750 limited, my Ducati and most of my Harleys and I think they are superior.

[Sailariel]

Had a dry clutch on my NSU 250, BMW R-60, and BSA 650. The only clutch problems I ever had was with the BSA. As Alex said, the technology has come a long ways--so it`s a wash.