Now I have never worked on a clutch before and it seems the more I look into it the more confused I get. My bike is apart for a winter deep clean and I've taken the clutch plates out. It looks like the plates are steel and the basket alloy - is this normal? The friction material looks very thin to my untrained eye but measures 2.9mm total thickness so I'm guessing that's ok? Total stack is 38mm. The basket is a bit notched but nowhere near as bad as some I,ve seen. So to do the mod all I have to do is swop the first steel for a worn friction. Have I got it? right? If I'm right does anyone have an old friction I could buy? I know @oldrider is a keen advocate of this and I would really appreciate your input. Thanks
No, it's not normal to have an alloy basket and steel friction plates as they will cut into the softer alloy. However, it is normal to have steel plain plates - are those what you are referring to ? The friction material is very thin from new and will last a long time. If the stack is 38mm, this suggests the plates are fine. The conventional theory used to be that you needed to add a friction plate at the bottom and leave the rest alone. However, I have become convinced that this is not necessary and it's not what I have in my own stack now. All you need to do is re-order your existing plates with a friction plate at the bottom and make sure you basically alternate friction and plain plates. You can have two plain plates paired together but it's not normal to pair friction plates. I have a very low stack height in the low 30s. The advantage of this is low lever weight due to reduced preload on the springs but the risk is possible slip. I'm not getting any slip but if I should, I can simply add a plate or two. So, don't be afraid to go below the 38mm you're at now. I do have spare friction plates if you need one but try the re-ordering method, it works well.
The friction plates should be alloy. Plains are steel. If you have steel plates buy a set of newfren from ebay. About £50 a set last time I looked. Make sure you order alloy. Use steel friction as 1st plate for qc mod. Have seen ferodo plates on ebay similar price. Not tried them. Only problem with newfren is they can stick together if left unused for months but they seperate without any damage in my experience.
OK. Thanks for your replies. I was thinking my friction plates were Steele cos I pulled them out with a magnet. Having just checked again it seems it is the friction material that is magnetic (ferrous?). The actual plate is indeed alloy. So Ill give the reordering method a go. It is still beyond me why this would stop the clatter but I also don't see how it could do any harm.
The 1.5mm plain is dished. It can go anywhere in pack. Should face pointy side outwards. Check with straight edge to check for dish.
Yes, the friction material is sintered with ferrous particles. Enough for a strong magnet to pull them out, which is jolly handy. Ime, used plates can be preferable to new in this specific application because new plates have sharp edges which catch in the notches and then cause serious drag. The clatter is stopped because by putting the friction plate in first, it is able to drop down into the bottom of the curved, rounded section at the end of the basket slot. It then lodges there and can't oscillate. This in turn stops the rest of the stack from oscillating so no clatter. The plain plates sit in slots that have square ends to the slots and the first friction plate normally sits on top of the first plain, where the slot sides are parallel for both sets of plates, leaving both sets free to oscillate and chatter.
Think I've got that-thanks. The convex plate is very difficult to spot without a straight edge but it is stamped with a letter O so if anyone else is doing this look out for it.
I don't think it's standard to have a letter O. Normal is to have a stamped dot in line with the half-moon cut out and at the level of the base of the inner 'teeth'. I couldn't detect any dishing with mine, even with a straight edge. Still works fine though.
It could be the o was stamped by previous owner to identify the plate. The dishing is so minute that when laid flat on a mirror I can just slide a sheet of paper under it. I'm guessing 1 degree from horizontal. I just cant imagine what difference it could possibly make.
To add my thoughts on clutch plates in general - When I have had any clutch apart I have always de burred the plates (the part that engages with either the drum or the splined hub . This helps them move smoothly rather than grabbing . So remove sharp edges ( or put small chamfer )with a file to the tags on the friction plates and on the "teeth" of the steel ones where they slide on the hub .
My experience, at least with a basket with some notching, is that it is new plates that have sharp edges which catch and prevent the plates from separating nicely. Old plates may have some burring but that burring doesn't catch. When I replaced my plates with new ones, they caught so badly once the engine started to warm up, that the clutch drag made the bike pretty much unridable. I cured it by replacing the top few new plates with old ones. This completely eliminated any drag.
I have also in the past filed out the "notches " in the basket to aid smoothness . Not on a Duke tho .
If you hear the sound of an oscillating Ducati dry clutch as music and don't mind changing friction plates and basket every few thousand miles, that's fine by me. If I hear it as mechanical mayhem that's causing unnecessary and avoidable wear, so choose to do something about with a simple, elegant fix, please grant me the same leeway.
@Old rider Yep got it done. Sounds much better. Not had chance to ride in anger yet but it snicks in and out of gear lovely. On a test up and down the drive it feels a bit "snatchy" but I'm hoping this will bed in with use. Thanks for all your input.
Did you put any new plates in? If so, make sure you try it fully warmed up before setting off on it. The mod itself shouldn't affect snatchiness one way or the other.
No only old plates reused. To be fair once up and down the drive on a cold engine is not really a fair test. Soon as I get a good ride in (could be a while) Ill report my impressions. Loving the sound, or lack of, though.
Should be just fine on old plates If you want to cure grabbiness, there is a mod for that but it's even more controversial. Merry Xmas!
A question re the clutch friction material if measured does anybody know the approx thickness when new or when to consider replacing. I going to inspect over the holidays its got 29k miles on and as rattley as but doesn't make any strange noises or slip Going to do this mod, if the plates require replacing as i think they may do you replace the basket at the same time. Cheers
