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Adjusting the pressure plate on a 350 mark 3
Posted: Wed Jan 12, 2022 9:27 pm
by neal69duc350d
Hi all,
Just replaced the clutch on my '69 350 mark 3D. After adjusting the clutch lever, and testing the action with the new plates and springs, I noticed that the pressure plate does not extend evenly from the clutch basket. One side is clearly higher than the other. I've tightened down the screws fully on the pressure plate springs, as the workshop manual states. On other bikes, I am used to loosening the screws to reduce some of the tension on the springs to ensure the plate extends evenly all the way around. Should I follow the same procedure here? I checked the pressure plate and it is flat.
Thanks,
Neal.
Re: Adjusting the pressure plate on a 350 mark 3
Posted: Wed Jan 12, 2022 10:18 pm
by graeme
The tangs that align the plates to the clutch basket can dig into the basket over time and not allow smooth movement, a file can clean the rough edges.
Also for the inner, same a round file or dremel to clean the rough surface.
Look at the tangs on the steel plates, burs should be removed.
Also check all the springs are the same length and tension
Graeme
Re: Adjusting the pressure plate on a 350 mark 3
Posted: Wed Jan 12, 2022 10:29 pm
by blethermaskite
The tension of your set of clutch springs may be slightly unequal, best course of action is to swap around the positions of the individual springs to hopefully equalise the overall pressure on the lift plate, as a bodge

you can play with a suitable thickness washer under a 'weak' spring. You cannot adjust the lock screws that secure the springs.....if they are not properly tight they will unscrew themselves and potentially cause significant damage. Agree with Graeme check the clutch basket and hub for wear.
Cheers
George
Re: Adjusting the pressure plate on a 350 mark 3
Posted: Thu Jan 13, 2022 8:01 am
by Bevel bob
After checking all the usual suspects ,I fine tuned my 250 clutch with a thin washer against one spring.
Re: Adjusting the pressure plate on a 350 mark 3
Posted: Thu Jan 13, 2022 12:17 pm
by themoudie
Aye Neal,
Have you dished steel clutch plates? Even minor warping will impare the clutch action and the 1mm steel plates are prone to this. Check them on a face plate and if there is any rocking they need to be in the scrap/recycle bin.
On my '74 450MKIII the clutch could be a bit of a drag, especially in stop start traffic, when using SAE40 and standard steel plates. Having de-burred the clutch centre, basket and the plate tangs the problem was not as severe, but still remained; even though the pressure plate lifted squarely, a new set of springs fitted, with all the lock screws tight and a touch of nut lock fluid on the threads.
Changing to a set of 2mm thick steel clutch plates, with spacer for the clutch centre, to maintain the correct spring pressure and using a 15W/50W synthetic oil has eliminated any drag from the clutch and enables positive gearchanging under all circumstances.
Good health, Bill
Re: Adjusting the pressure plate on a 350 mark 3
Posted: Thu Jan 13, 2022 2:05 pm
by neal69duc350d
Thanks all. Appreciate the suggestions!
I should have mentioned that the steel plates are new and true, as are the springs. They are all equal length (30mm) but I have no way of checking the compression tension. I will double check that the basket and hub are smooth and free of ridges, and file them down if needed, and also try various combinations of spring position and thin washer spacers to see if I can equalize the pressure on the clutch plate.
Compared to my Triumph Bonneville, which is a royal pain to adjust the springs on the pressure plate because they are very "grabby" (I have ruined so many springs this way

), adjusting on the Ducati is much more straight forward. I will follow the workshop manual as advised to fully tighten the springs down.
Neal.
Re: Adjusting the pressure plate on a 350 mark 3
Posted: Thu Jan 13, 2022 8:36 pm
by LaceyDucati
It's also worth checking the pressure plate. Quite a lot of the adjuster screws are not true or central to the plate face, caused by the central thread being spot welded skew.
Regards Nigel