clutch ball bearing

[DewCatTea-Bob]

By: 'evil'...
" Here is the diagram I went by: "

____ As can be noted within that particular drawing (from a questionable-source), aside from the 4 pieces (of the complete-set of 6), which are easily seen together & drawn above the clutch-basket parts, (which those 4 pieces go-through the center of),, the 5x5mm isolator-barrow/roller (shown in this case) has been drawn to be located right-next to the screw-adjuster/rod.
That drawing, found within a (past)- popular workshop-manual, is likely the only reason for why I've found the 6-piece set arranged in that very same (non-sense) order, as well, within a number of old DUKE-motors.
However, as any mechanical-type with at least a fair-sense of engineering could realize, it makes no good-sense what-so-ever for that isolator-barrow/piece to be placed in that particular location ! _ As at THAT end of the line-up (of the 6 pieces), EVERYTHING rotates at the SAME rate !!
__ I once thought that that barrow/roller-drum piece was simply just an add-on extension-piece from when Ducati chose to make their 4-speed transmission into a (wider) 5-speeder. _ But I've since reasoned that it's main-purpose is to help isolate the rotating pieces from the 6th-piece (in line), which must be kept from rotating (along with the other 5). _ The theory here is that that short (only 5mm-long) rod-piece has as little circumference/contact-area as possible, so as to maximumly reduce it's -(a rod-piece's) surface-contact with the inside-surface of the rotating main-shaft. _ Thus providing as little as possible rotating-force to be transferred through to the (expected to be) stationary rod-peg, which it itself must make direct-contact with the stationary inny-button (that's pressed into the lever-arm), whenever under clutch-disengagement pressure.
__ So I recommend that my suggested 6-piece line-up order, (as so well diagrammed by Tony), be followed, not JUST because Ducati's parts-books do NOT agree with that particular depicted Clymer-drawing -(indicating it's suggested-position for the isolator-barrow/roller piece), but ALSO because it must also help to increase the isolation of the additional rotation-force by the longest-rod -(as THAT rod has much greater inclination to rotate along with the main-shaft!). - (So ya see for that reason, it's better that the last ball [in line to the right-side], be pushed-against the very-short barrow-rod, rather than the longest-rod!)

____ I've tried to use Microsoft-supplied software on my PC to erase all but the relevant-parts from the (previously-posted) diagram but, the process unfortunately looses much detail and also adds dirt/noise to the alteration ! _ Sorry but that's the best I can do with it, however if ya alternately also look at the original diagram, ya can then make-out what's what well enough.
I thought it would be more helpful to see where all of the 6 pieces are arranged in the previous-diagram.
It calls the 'barrow/rod' a "roller" -(which it actually indeed is), but I prefer not to refer to it as such because in this case it's not used as a 'roller' !


DUKE-Cheers,
-Bob

[evil]

So I got chrome ball bearings at the local hardware store but, I am missing the short "roller" piece. Know where I can pick up one of those?

And as I said before, the lever is really hard to pull. Like it hurts... hard to pull. Think having the roller missing would cause that? And-- is a chromed ball bearing going to work or does it need to be all steel?

[MotoMike]

I don't have experience with the ducati clutch but it seems pretty similar to other motorcycle clutches I've worked on. I don't know what grade the chrome ball you got is, but I would want a ball that was specifically designed for high loads. If the ball is too soft it will get ground down and impart more grasp to the rods. this might be insignificant.

I can't see how the missing roller would cause a very hard clutch lever unless the missing length caused the actuating lever to engage the end rod at more of a side angle than axially with the various parts. Is it possible that there are heavier springs in the clutch pack than stock? Assuming you made sure all the rods and balls move freely in the center of the shaft and your clutch cable and lever are free and well lubricated.

Getting my mind around the different part positions and the benefits of one order over the other is an interesting topic.

Looking at the parts it seems that Ducati relied largely on the 4 very small contact areas at the ball to rod interfaces to be incapable of transfering the torsion imparted to them when the clutch lever is pulled. The balls and rods being made of very hard steel combined with what ever oil gets into that shaft center to additionally lessen the grasp of the metal to metal contact. It seems to me that it is these relationships that really effect how much rotation is carried through to the last rod on the right side of the assembly where the actuating lever is. When the clutch lever is released those parts should have no axial force on them as a bit of free play is prescibed in the linkage. During this time, I wonder what is really happening to those parts inside the shaft. Owed to friction and a bit of viscous coupling from what oil is in there, do the parts all rotate at the same speed as the shaft? Or because of thier mass resisting movement and the vibrations of the engine distubing the coupling and friction by minutely bouncing these pieces where the sit loosely contained in the center of the shaft, do they do something different? Do they rotate at some lesser rate that varies with speed. I think it is the latter and that in reality it makes no appreciable difference which order you select. It's just my guess.

[wcorey]

In my Haynes manual for mkIII and desmo, the assembly instructions, both written and pictoral, indicate the order (from right to left) as short pushrod, bearing, long pushrod, bearing, roller.
However the exploded diagram shows two rollers and one bearing in the following order, short pushrod, roller, bearing, long pushrod, roller.

What I found in my R/T motor looks to be partially home brew with a 5mm shorter short pushrod and 10mm roller.

I'm assuming they call it a roller because it looks to be an actual bearing roller, even though it doesn't serve that function in this application.

Owed to friction and a bit of viscous coupling from what oil is in there, do the parts all rotate at the same speed as the shaft?

One thing to consider is that the short pushrod goes through a rubber seal that would tend to hinder it's rotating at pace with the rest of the components.

[evil]

I put in the ball bearings and that clutch is still really really hard to move.

What could it be? I lube dall the rods and bearings up...??? I pulled the cable with the clutch not attached and it was fine.
As soon as I put it all together it was still way hard to pull?

[MotoMike]

I put in the ball bearings and that clutch is still really really hard to move.

What could it be? I lube dall the rods and bearings up...??? I pulled the cable with the clutch not attached and it was fine.
As soon as I put it all together it was still way hard to pull?

Heavy springs in the clutch pack? An extra disc? seems like the only place for the pressure plate to bind would be where the spring retainers mate with the bosses in the bottom of the clutch drum. And it seems that with wear they would get looser rather than tighter.

be sure to let us know what it is.

[ajleone]

Evil,
Interesting - I looked in my shop manual (same as yours) and clearly it does not match the parts book.

Maybe one of them is "...only a suggestion..."
tony

[bettyann]

Evil
Just because you put all the correct balls,roller,and rod ect. in the hollow clutch shaft, it can operate lousy or great.
The problem comes is how you adjust the clutch center adjuster then the clutch cable. Ask Dew cat tee bob, Sydney Tunstall,
Mick Walker. or any Ducati owner with years of experience, with how important the these settings are. That adjuster on the clutch center isn't to adjust the clutch cable, it's to set to fulcrum advantage of the lever under your shifter side cover.
Capt. Paul

[evil]

Capt. Paul,
You just made total sense.
Thanks,
Evil

[DewCatTea-Bob]

_____ WOW, if I had had any idea that there would be so much follow-up response by all of those of us above, then I would've made a point to get-back to finishing my related-post on this subject much sooner !
Still, it seems to me that either my previous posts on this, haven't been read or weren't understood !? _ So please always ask for any further clarification of any wording I've used, (in ANY of my posts) !


By: 'evil' ...
" I am missing the short "roller" piece.
the lever is really hard to pull. Think having the roller missing would cause that? "

____ No, not directly... The barrow/roller's job doesn't have any effect on that issue, however if the clutch's adjuster-screw/rod was adjusted for when the roller was in place (within the 6-piece line-up), and then got removed, but yet the screw-adjuster was still left as was (and not readjusted to compensate for the lack of the roller/spacer's length), then in that case, the lever-arm will then tend to (also) press-downward on the rod-peg, (perhaps with as much [wasted] force as that which is needed to push the rod-peg inward), thus divert/split the lever-arm's pressure, towards other than optimumly intended.


" I put in the ball bearings and that clutch is still really really hard to move.
I pulled the cable with the clutch not attached and it was fine.
As soon as I put it all together it was still way hard to pull?
What could it be? "

_____ There's a couple of common-issues that can cause the clutch-pull effort of a narrow-case (& even a w-c) set-up to be extra resistant to disengagement-operation ! ...
In this case, it's fairly-likely that the optimum-angle for the lever-arm has not been adjusted as I had recommended doing within a previous-post (in the other thread about the cable-installation).
For those who did not comprehend what I had instructed (there), here's another try.....
____ Adjust the motor's internal clutch-adjustment -(that screw-adjuster/rod & nut), so that the lever-arm will (ideally) be exactly at a 'RIGHT-angle' (no pun intended!) to the outer push-rod/peg, at the same point when the hand-lever is at the mid-point of it's OPERATING-range -(that's not including the intended slight pre-slop which ought be left at the handle).
When that adjustment is near/at it's best, (then due to the arc of the lever-arm's fulcrum-point), the lever-arm will then start-out pushing inward & upward and end-up pushing inward & downward, (instead of starting-out pushing directly inward, and ending-up pushing more downward & less inward, thus at that point wasting it's effort, [since the inny-button of the lever-arm is then trying to bend the rod-peg (downward), instead of pushing it (mostly) straight inward (as intended)] ).
I know for a fact that, (due to the bowl-shape of the inny-button), if the lever-arm is left adjusted so it's at an angle that leaves it set too close to the motor-case, the clutch will then become next to impossible to fully disengage, (without the binding-up issue [that's very likely occurring in this case], due to the tip of the rod-peg getting jammed up into the top-inside of the inny-button).
The symptoms of this type of maladjustment are that the hand-lever will (at-first) pull-in easily enough for about the first-half of it's range, and as the lever gets nearer & nearer the handlebar-grip, it gets harder & harder to further pull-in,, and yet your Duke still wants to creep-forward, anyhow.
____ With the opposite-type of maladjustment, instead of the clutch not fully DISengaging, it will instead not become fully-engaged (and possibly slip with the stress of increased throttle).
So when this clutch set-up job is being done, it should also be checked that the lever-arm (or anything left overly sticking-out on it's outermost-side -[such as excess inner-cable or non-stock cable-clamps] ), is-not getting blocked-up against the inside-back of the shifter-cover (once back in-place), or-else clutch-slippage may become inclined to occur.
(All this extra fussing is what most other [nonDUKE-mechanic]- mechanics overlook [in the n-c models] !) _ You can note if this has ever been an issue for your Duke in the past, by looking for significant scratch-marks or worn-areas where the outer/back-side of the lever-arm (or related parts) may have been rubbing against the inside-surfaces of the shifter-box eng.cover.
__ All this set-up fussing should be all worked-out before finally FULLY-tightening the inner-cable's clamp. _ And to make this extensive (& extra-tedious, [compared to the w-c.setup] ) job much-less painstaking,, it rather helps to always leave the tip-end of the inner-cable inserted into it's place within the hand-lever handle, but with the hand-lever's fulcrum-screw -(which also holds the hand-lever handle to it's handlebar-support), left unlocked & ready for screwing in & out of place, for each time ya need to check for proper-operation (after each step of this otherwise extra taskful job).
____ The other common-issue which tends to contribute to clutch-pull/operation difficulty, is the particular chosen route which the clutch-cable may be forced to run-through between it's hand-lever & it's opposite mounting-point where it has to connect at the motor.
Any clamp-down points or small-radius bends will add considerable resistance to the cable's operation !
__ I will advise of the best possible cable-routing (to avoid unnecessary resistance-pressure) for the clutch-cable, within the other thread concerning this cable topic. -
viewtopic.php?f=3&t=368&p=2424#p2424


Hopeful-Cheers,
DCT-Bob