Clutch Questions

SandPebbles

SandPebbles

Junior member
Location
Madison, CT U.S.A.
I've have a few questions regarding the clutch assembly of my '74 3C.  When taking apart the clutch, I found a thick washer under each of the clutch springs...between each spring and the pressure plate.  The washers appear to be an aluminum crush washer with the open side towards the plate.  I have new springs to install and I haven't seen these washers on any parts diagram.  Are they
supposed to be there? 

The bike also has a hydraulic actuator for the clutch.  I can only guess the previous owner converted the bike as I think the bike should have a cable actuated clutch (Bike is S/N 1592).  I intend to keep the hydraulics but have read about the problems of the system leaking and building up pressure behind the slave cylinder and cracking the casing.  One remedy I've seen referred to in the forum requires drilling and tapping the hose connection deeper so it threads into the slave cylinder thus sealing the fluid from the casing.  Are there any diagrams, drawings or procedures out there that give any dimensions, thread sizes or depths for the fix?
Any help would be grateful...thanks.

 
Someone has added the washers to add a bit more spring tension. some times you find them under just a few springs, this is done to balance up the spring load if the clutch pressure plate does not lift evenly.
 
Obviously it needs washers under the bolt heads, but not between the spring and pressure plate. As Paddy said, someone has used them to increase spring pre-load, which might be because the clutch plates are a bit worn. As the plates wear down, the spring pre-load decreases to the point where the clutch may start slipping. Adding washers is a simple and practical temporary fix (until you replace the plates). I suggest you measure the thickness of the friction plates. New plates are a bit over 3mm thick. The workshop manual says the minimum thickness is 2.5mm. But my old plates were slipping badly at 2.7mm.

Cam
 
Thank you for the replies gentlemen.  In addition to the new springs, I also have a new set of plates I will install.  I plan to assemble without the washers between spring and pressure plate.

Any helpful advice on the hydraulic hose connection to the slave cylinder?  I did use the search function on the forum but found nothing specific for this fix. 

 
AFAIK attempts to correct the poor (180) design have met with varying levels of (non-)success.  I've not attempted one but just from my mental image, the problem is that it's quite hard to really seal onto the inner cylinder in the cover.  The inner cylinder is only a few mm in wall thickness, the fitting seals on a flat face and thus you need to get that flat face all the way down to the inner cylinder to keep the hydraulic pressure away from the interface between cover and cylinder.  At a guess taking the sealing face (or even a more compact revision thereof) that far down means you have insufficient thread depth to allow proper tightening of the hose.  Unfortunately it's just a crap design, fixed - like so many other things - in the 120's. :)

Hence Keith's solution of machining the whole mess out and elegantly replacing it with a Ducati slave, or Red's new and quite different cover (still in beta testing?).
 
Here's a link to a series of posts that describe the early hydraulic clutch problem and a simple fix for it.  I purchased the bits for the fix from Wolfgang.

http://www.laverdaforum.com/forum/index.php?topic=67298.0

Tom
 
Again, thanks for the replies.  The link from Tom was very helpful and provided the drill size I was looking for.
I can make up the drill guide from a M10 x 1.0 hose connection, but I really like the modified hose fitting with
dimple that Red had posted.  Are these fittings still available from Red or Wolfgang?

Tom, what actual bits did you get from Wolfgang, and how long ago?

John
 
John,  Wolf supplied the drill guide, the extended adapter for the hose, as well as a drill bit.
Also needed a new o-ring and rubber boot for the slave cylinder.  Was about two years ago.
 
SandPebbles said:
Are these fittings still available from Red or Wolfgang?
John
Click to expand...

got sick of machining them so I made a couple of sets last month and gave one set to my CNC mate
he is going to knock out 25 sets for me hopefully this month as have another person wanting a set as well
if you can wait that long can send you a set in 3-4 weeks time

normally would be quicker then that but we are doing a run of 30 billet alloy hydraulic clutch covers at the moment and they burn up a lot of my allotted CNC time

 
Tom and Red, good to know parts are still available...

Red, there is no rush (we are expecting another 8 inches of snow by tomorrow morning) on the set.  If you are going to post
a package from Australia, we might as well make it worth your time.  I also want to purchase your Ignition and Alternator kit for
my 180.  Are you still selling them direct?  Please let me know, either way I will message you in 3-4 weeks regarding the clutch hose fittings.

All the best...
 
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