clutch ball bearing

[DewCatTea-Bob]

By: Mike...
" 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. "

____ This notion is indeed a possible cause, providing that my advice given in the other thread (concerning the cable), was ignored and the clutch adjuster-screw/rod was then not properly set (to make-up for the missing-length of the absent barrow/roller piece).


" 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? "

____ It's a certainty that all of the first 5 (of the 6) pieces most-always rotate right-along with the main-shaft ! _ Only when the line of pieces are subjected to the pressure of being squeezed by the (set of 6) clutch-springs during clutch-disengagement, does each of the center 4 pieces vary in rotation as they then take-up sides in the battle between the rotating adjuster-screw/rod and the stationary rod-peg, at the far-ends (of the 6 piece line-up) !


" 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. "

____ Well if we go-ahead & bother to further scrutinize exactly what the 4 independent pieces are actually doing at all times in a running-motor,, it's indeed likely that their rotational-speed takes a short-moment to get accelerated or decelerated to the new rotational-speed of the main-shaft, during any drastic changes in the RPM of the motor & it's main-shaft.
Furthermore, there are probably a few RPM-induced harmonic-frequencies set up, which are possibly capable of actually suspending the two balls (and maybe even the roller) away from the inside-walls of the main-shaft, thus creating a lack of constant-friction between the balls & the main-shaft which may then, (for likely a short time), allow the balls to (very slightly!) decelerate their momentum (from whatever the previous rotation-rate, of the main-shaft). ---
(Okay, let's please not make any further fun of how far I tend to dive-into minor-detail.)


" in reality it makes no appreciable difference which order you select. "

____ It's probably true that the exact line-up order of the 4 center-pieces (between the outer 2, of all 6), actually makes no big difference.


Dukaddy-DUKEs,
-Bob

[MotoMike]

hehe.. who would have thought a 3/16" ball or two could generate so much discussion. It is fun to ponder such things. Thanks

Mike

[evil]

OK so.....

Since no one coughed up a resource to buy the 5mm roller, I threw ANOTHER 3/16 ball bearing in the mix. I won't even tell you where (how exiting).
I read all your posts and determined that I needed to check the adjusting screw. The book called for 5mm pertruding from the holding nut, I set that.....then moved the arm that gets attached to the clutch cable to 90 degrees (pretty much in contact with the rod), I set the clutch cable (at the handle) fulcrum. And...... it worked (mostly).

It was MUCH easier to pull..... not super easy, but definetly well withing the range of drivable. It looks like the (2nd) previous owner put in new clutch disks so maybe a little wear in time is necessary too.

Either way, I took the Duc for a spin this afternoon and had the best ride yet. (2nd ride since the early 90's)

I know there has been a lot of dust kicked up over a little bearing.... but sometimes the littlest things make the biggest differences.

Thanks again for all of the really great advice. I have read and re-read all the posts and they got me riding correctly so

THANKS THANKS!!!

P.S. 5mm roller for sale? Anyone?

[DewCatTea-Bob]

" The book called for 5mm pertruding from the holding nut, I set that.....then moved the arm that gets attached to the clutch cable to 90 degrees "

____ Sorry to say but, that only took ya into the right-direction, and not quite far enough...
__ First, the recommended 5mm of unused-thread is just a rough starting-point for getting the lever-arm into it's normal angle-position ONLY when ALL the stock 6-pieces are all still kept in use ! _ So when the 5mm-roller/barrow-spacer is replaced with a slightly shorter piece (or nothing), then it's to be expected that at least some of those left-over protruding/unused threads get sunk into the locking-nut, so as then make-up for the insufficient total-length of the line-up of pieces.
And also, ya need to shoot for setting the lever-arm (to it's normal-position) at a point that's slightly PAST 90-degrees.) _ That way, as the lever-arm is pulled-inward, it will first reach the optimum 90-degree angle before then falling to under the 90-degrees and thus begin to press-down on the rod-peg (instead of just inward as preferred).
So it seems that you ought to reset your clutch adjuster-screw inward another turn or so, to get even more improvement.


DUCATIly,
-Bob

[DewCatTea-Bob]

By: 'wcorey'...
" In my Haynes manual for mkIII and desmo, the assembly instructions indicate the order as short pushrod, bearing, long pushrod, bearing, roller. "

____ Alright except that it would help to clarify that you (likely) meant from right-side TO left-side.


" However the diagram shows two rollers and one bearing in the following order, short pushrod, roller, bearing, long pushrod, roller. "

____ That's got to be due to the confusion concerning the correct order for the line-up of all those different pieces.
While the use of only one ball (to depend on for doing it's function), will probably work well enough,, that suggested second roller/extension-piece must be some kind of error, as there's no sense for it to exist (in place of a ball).
__ Originally, the 4-speed motors did not include the extra/6th-piece, but Ducati later needed to add the barrow-roller extension-piece, so as to make-up for the longer 5-speed main-shaft. _ But that addition must have been to 'kill-2-birds-with-1-stone', otherwise Ducati could've simply made the longest push-rod slightly longer (for the n-c 5-speeder), just as they chose to do for the (even longer) wide-case main-shaft.
__ It should be clear that the barrow/roller-peg was not added just merely to supplement the insufficient-length of the long-rod (of the 4-speeder), since the wide-case's (required)- longer version of the long-rod was not also made longer enough to eliminate the 5mm roller-peg as well, at the same-time. _ So since Ducati chose to keep their new/longer version of the long-rod also still short enough to retain the use of the 5mm roller-peg, THEN that peg must have already been deemed needed to serve another useful-purpose (other than as just a mere extension-piece) !
And I can see no other use, other than to allow the use of another ball ! _ So therefore, I suggest that my suggested-arrangement, be chosen,, for the line-up of the 6 pieces.
A third ball could be used (so that there's then one ball between all of the pairs of flats), but, at the left-side of the line-up, there's no real need for a ball's function (of isolating flats apart), since everything at THAT end all rotate at the very-same rate, at all times.


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

____ I've never come-across such a line-up of pieces in either n-c or w-c motors... I'm thinking that someone in the past may have had to add the 10mm piece, to go along with a shorter narrow-case piece, (after acquiring a non-correct replacement-part).
In a 450-R/T, the rod-peg should be 33mm long, and the long-rod should be 165mm. _ So you may now be better able to figure-out the reason behind the changes you discovered.


DUKE-Cheers,
-Bob

[wcorey]

____ Alright except that it would help to clarify that you (likely) meant from right-side TO left-side.

edited my previous post for better clarity...

____ I've never come-across such a line-up of pieces in either n-c or w-c motors... I'm thinking that someone in the past may have had to add the 10mm piece, to go along with a shorter narrow-case piece, (after acquiring a non-correct replacement-part).

I would guess that someone lost the 5mm roller, happened to have a 10mm roller and rather than shortening it, took 5mm off of the small pushrod instead (the end looks cutoff as opposed to turned like the proper part). Your guess is as good as mine though...
I was very fortunate in that I had the proper stock bits to replace the odd ones. I picked up a misc. lot of parts from ebay that I bid on mostly for a clean looking 428 16t countershaft sprocket that was included in the pile. It has turned out to be a real goldmine, lot's of nice clean replacements for some of the original rounded over nuts and bent-too-many-times tab washers.

In a 450-R/T, the rod-peg should be 33mm long, and the long-rod should be 165mm. _ So you may now be better able to figure-out the reason behind the changes you discovered.

Thanks for that info, i was going to ask about the long pushrod to make sure that wasn't altered also but it's 165mm so I'm ok there.

P.S. 5mm roller for sale? Anyone?

I can't imagine that Syd's (727) 522-3333 doesn't have them... I looked in my bearing draw to see if a had something I could cannibalize, but only have tapered stuff.
If you really can't find one I can easily grind my oddball 10mm long one down to 5mm and you're welcome to it...

[DewCatTea-Bob]

" I would guess that someone lost the 5mm roller, happened to have a 10mm roller and rather than shortening it, took 5mm off of the small pushrod instead (the end looks cutoff as opposed to turned like the proper part). "

____ I'm now sure that you're quite likely right on that. _ And that would then mean that the stock 33mm rod-peg is now at only 28mm or so, long.
I think that who-ever did that should've instead chosen to take the excess 5mm off from the long-rod rather than that rod-peg however, cuz the way that they chose to go, then keeps the rod-peg 5mm less inward into the main-shaft (which then of course allows more wobble/end-play).


" If you really can't find one I can easily grind my oddball 10mm long one down to 5mm and you're welcome to it... "

____ I think that special 10mm-piece ought to be saved & kept by someone who has a collection of both n-c & w-c motors & parts, as they may more likely need it (to go with a n-c long-rod in a w-c motor).


Dukaddy-DUKEs,
-Bob

[DaveSmith]

I know this is an old thread, but I'm trying to get my clutch working correctly. The bike came to me from parts bikes rapidly slapped together so there's been plenty of jerry rigging. Two Duc mechanics (Bob Brown, Ian Gowanloch) have looked at the clutch and both said, "It's put together in a weird way. Leave it the fuck alone and hope it doesn't cause any trouble". It started acting up last fall in heavy traffic.

I'm going to get the parts and try to put it together according to Bob's diagram with the cable routed how he said. How long are the rods?

Is this correct?

Adjusting screw. 3/16 ball bearing. 5mmx33mm rod(?). 3/16 bb. 5x5mm rod. 5x10mm rod(?)

It's a '65 250 nc with a 5 speed.

[DewCatTea-Bob]

" I know this is an old thread, "

____ That's no matter at all ! _ As it's actually hoped & somewhat expected that our members find their topic-issues (which have already been covered) for themselves, (instead of starting NEW threads on the very-same topic).
__ You may likely also make-use of the related-info found with this link... viewtopic.php?f=3&t=1156&p=7861&hilit=clutch+lever-arm#p7856



" How long are the rods? "

____ Unfortunately my parts-book only gives the length of just the short-roller (as 5mm, [which was added to the push-rod line-up for the 5-speed trans] ).


" Is this correct?
Adjusting screw. 3/16 ball bearing. 5mmx33mm rod(?). 3/16 bb. 5x5mm rod. 5x10mm rod(?) "

____ That's indeed the same order which Ducati them-self had those parts lined-up in,
however it seems to me that the last/right-side rod/peg in the line-up is more like 30mm-long, (not just "10mm") !


Hopeful-Cheers,
-Bob

[LaceyDucati]

Hi
The short rod with one rounded end, which I call the nose is 33mm long on 5 speed models. This goes at the far right hand side, rounded end to the clutch arm.
The long rod is 156mm on a 5 speed N/C and 165mm on the W/C.
Nigel