My darn clutch again

A

Axel

New member
Location
Norfolk
As anyone tried running the clutch with a. 4 instead of 6 springs or b adding a washer or two to all 6 springs to reduce the preload?
Roger
 
Axel said:
As anyone tried running the clutch with a. 4 instead of 6 springs or b adding a washer or two to all 6 springs to reduce the preload?
Roger
Click to expand...

WHY? :o

If your clutch action is too heavy, check if some DPO has fitted 6 heavy-duty SFC springs (or some other non-standard springs).  Combined with a sub-optimal cable and/or lever assembly, these can be near impossible to pull without bodily harm.

In my experience, there is nothing wrong with the Laverda clutch with stock springs and if all plates are OK.  Many POs have "up-graded" with stronger springs to cure clutch slip, when all that woud have been required was a new set of steel plates, I find very many that are bent/warped/buckled/burnt.  In fact, in just about every second clutch that I get to inspect.  Once the slightest defect through abuse has crept in, there really is no cure other than replacement.  It only gets worse...

Carefully setting up the pushrod length and actuating lever angle also goes a long way to achieving a compliant clutch action.  The rather heavy stock action can be noticably reduced.

piet
 
Piet
I appreciate your comments and experience, many thanks. My next move is to open it up and check the plates as you suggest. By the way whats a DPO and PO (past owner?)
Roger
 
I run both my ex racing triples and Sf's with SFC springs and an extended clutch lever. Having small hands I find this set-up works a treat.  After more than 20 years I have never ever seen any of my clutches again as they never slip or drag and are easy to disengage. One journalist described my triple as having a clutch that "Could be pulled in with the fingernail of my little finger" - possibly a slight exaggeration. I'm not a "DPO" but a VEO" (very experienced owner) - These are my experiences over many years and quite a few Laverdas - Regards - Phil
 
According to Dam racing's website there are 3 different springs. Heavy duty 8 coils with a spring rate of 38kp. Standard duty 9 coils and 33kp and Lightweight 9 coils and 27kp used in the 500, these are out of production. So Phil which do you have? Dam Racing recommend a mix of 3 haevy and 3 standard fitted alternately around the plate.
 
Hi Axel - I had springs made to the same specification as the SFC 750 (part No 50 120 019). They are heavier than the standard (006) springs but lighter than the F500 springs (089). I haven't had the springs made for some time now and will need to get a sample from my own Sf if I have them re-made. - regards - Phil
 
Axel said:
As anyone tried running the clutch with a. 4 instead of 6 springs or b adding a washer or two to all 6 springs to reduce the preload?
Roger
Click to expand...

Adding washers to springs increases preload and will make the clutch action heavier. It's sometimes done as a temporary measure to cure clutch slip when the friction plates are worn.  There should only be one washer for each spring (under the bolt head). If your springs have more than one washer that might explain why your clutch is too heavy.

Beware of using lighter springs. You may get clutch slip. You can try it if you like, but in my experience, Laverda clutches are only just capable of transmitting the full torque of a healthy triple engine, especially if still using the original friction material. I've had several that slip for one reason or another. 

Piet and Phil know their stuff. You won't go wrong if you follow their advice. Greg Parrish (DAM Laverda) is also pretty helpful. He sells an extended actuating arm that might solve your problem. https://damclassicracing.com.au/43301003-3-dam-easy-clutch-mk3_std/
 
Dellortoman
Thanks for your advice.lve ordered a MK3 actuator arm from Greg Parrish at Dam Racing. I'm baffled by your comments re additional washers as several sites say adding a washer Decreases the preload.
Roger
 
Axel said:
Dellortoman
Thanks for your advice.lve ordered a MK3 actuator arm from Greg Parrish at Dam Racing. I'm baffled by your comments re additional washers as several sites say adding a washer Decreases the preload.
Roger
Click to expand...

Depends on where they are placed.

piet
 
OK, I was imagining a washer of similar OD to the OD of the spring that will slip over the alloy boss that sticks out from the inner clutch hub.

What you're describing is a washer of smaller OD than the ID of the spring so it'll go "inside the spring" rather than "under the spring", which is what I understood Axel to mean.


 
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