750SF1 Clutch Pushrod Protrusion

[sfcpiet]

Difficult to justify tearing the primary drive apart to achieve the same result (for clients). No big difference fabricating a spacer or new rod. Silver steel, flame-hardened does the trick quite OK.

Your washers-under-the-lever-boss trick brings the heads of the fixing screws dangerously close to those of the sprocket lock plate. They almost kiss if a spring washer is placed under each!

piet

 

[Vince]

It can be tricky, playing around with my Pantah rear sets at one point it was so easy to go over centre and lose function. I was trying to get it to work in a tight space.

 

[sfcpiet]

For the sceptics;
Roller diametres are 8 and 12mm.



Their axles are located differently, 8mm on the left. This gives a definite ratio advantage, sacrificing pushrod travel.



The corresponding levers above each other. Lever for 12mm roller on top.



Difference in levers is hardly discernable. 12mm roller left, 8mm right.


I'm suspecting the change was brought around as the early Verlicchi handlebar levers were phased out for Lucas and later Tomaselli items to keep ratios and pushrod travel in the ball park.

The fulcrum with the 8mm roller would at least explain why some bikes have girlie clutch pulls.

piet

 

[Paul Marx]

For the sceptics;View attachment 88798
Roller diametres are 8 and 12mm.


View attachment 88799
Their axles are located differently, 8mm on the left. This gives a definite ratio advantage, sacrificing pushrod travel.


View attachment 88800
The corresponding levers above each other. Lever for 12mm roller on top.


View attachment 88801
Difference in levers is hardly discernable. 12mm roller left, 8mm right.


I'm suspecting the change was brought around as the early Verlicchi handlebar levers were phased out for Lucas and later Tomaselli items to keep ratios and pushrod travel in the ball park.

The fulcrum with the 8mm roller would at least explain why some bikes have girlie clutch pulls.

piet

Thanks for that.
Paul

 

[chrisk]

Who would have known? Huh, another school day for me

 

[Vince]

Do you have any idea what date or model fitted that change might have occurred Piet? So interesting.

 

[chrisk]

Do you have any idea what date or model fitted that change might have occurred Piet? So interesting.

True Vince. The combination of mismatched components could leave the uneducated banging their head against a wall for days.

 

[piranha-bro2]

Wonders never cease with the factory - you'd scratch your head for days and still not get it. I'll keep the silver steel and flame hardening in mind Piet.

 

[motoddrob]

Thanks Piet for pointing that out, never knew. My extended clutch action is wishy washy. I made my own extended leaver from 2 original leavers cutting and welding. The levers were brought off ebay USA back in the early 2000s from some one thast had a box full of bits and pieces he sourced many years earlier so could have been early stock. I'm thinking that Magura hydraulic lever Steve posted could be the go for the Motodd.

 

[sfcpiet]

Do you have any idea what date or model fitted that change might have occurred Piet? So interesting.

It must be kept in mind the earliest bikes had a largely different clutch design, seems this type would cope with less pushrod throw better than the later clutches. Iirc, this clutch had only 5 lined plates as opposed to the later 7, it was phased out around 1969-70. I've always found the Verlicchi-equipped GT and S clutch pulls to be far lighter than those using the Tomaselli handlebar gear. The Lucas stuff is somewhere in-between... stiff, but not too heavy as to be uncomfortable. As I've stated, I cannot find any different part #'s for the lever fulcrum for either the 750 or triples, perhaps the secret lies in the earlier nomenclature, which bears no relation to the later 12 345 678 number system.

With existing bikes often being bodged nightmares, I guess it's well worth a look-see as to what exactly is fitted when experiencing clutch issues, before booking into the loony asylum. Finding out about this cost me an afternoon of fruitless trouble shooting before I finally stumbled across it. Swapped the fulcrum out for the more common item and the clutch suddenly behaved itself.

We've now waffled on for ages over obscure stuff and the OP still doesn't know the correct rod protrusion... I've currently got a 750 on the engine stand, can measure tomorrow.

piet

 

[Vince]

Its a mine feild in Laverdaland. Good to have a guide mate.

 

[sfcpiet]

Rod protrusion, with part-worn lined clutch plates at an average of 2.80mm, rods and balls in as-new condition, is 12mm.

New clutch plates will reduce this by as much as 1.5mm, worn rods/balls and plates at around 2.6mm will increase protrusion by around 1.5mm.

piet

 

[henrywillms]

Piet, and others with such intimate knowledge..... As per the above threads us mere Laverda mortals who enjoy riding and maintaining our Laverdas really appreciate your knowledge and the time you take to share it and explain it so well.

It would be impossible for many of us to keep our bikes in the road without the help we get when we need it from you and others on the Forum. And I realize that some times the "search" function does not always get used as much as it could, or the search responses are not clear or hard to find sometimes, and so you end up repeating your yourselves.