C: Clutch Twin Clutch Drag

[Bill Thomas]

I have to leg trail, For a short time,
Mostly the left leg, People behind mostly hang back !!.

 

[Robert Watson]

Maybe that's how Rossi started the trend!

 

[Mikethebike]

Regarding end force, after concluding pilot clutch was not the problem I tried to repeat problem with pilot plates removed so I could watch shoes. Will post video in a minute I hope. I made a dummy outer plate from sheet steel (grey in video), and spaced it with washers and nuts. In video my black hand rotates the grey plate (simulated drive) and shoes can be seen to engage/centralise lovely.
Then I rotate the grey plate to engage shoes and pull in clutch, now shoes do not centralise until I let go clutch lever. The only thing the clutch lever does with this setup is to push grey plate, which pulls C13 outward. I then saw marks on the sides of plunger housing 'noses' and corresponding (but much fainter as steel) marks on inside of back C13 disc.
Back to video.. every time the shoes stay engaged is because my other hand is holding clutch lever in. Sorry can't show both hands. Thanks to Stu Spalding for his dummy clutch centre giving me this idea.

As a relative newcomer to Vincents. I’m glad to say I haven’t suffered from most of the problems in this thread, but tentatively offer the following observations:

The chainwheel PD20 should have minimal end-float, being shimmed, at either end, to bring it in line with the engine sprocket (which may also need shimming).

The C13 shoe carrier should also have negligible end-float, consistent with it rotating freely, to eliminate endwise movement when the clutch is lifted, and resultant fouling of toggles, plunger housings, etc.

The C20 nut is supposedly tightened until the sleeve of C3 expands by about 0.002” (!) – if the various faces are not square to the shaft, this will ‘cock’ C3 to one side.

If the shoe plungers do not contact their pins at rest, the simplest solution is to add 2 (hardened) rollers to the pins, rather than making new plungers, or boring out the housings.

The inner clutch plate, C21, should be checked for run-out, and for clearance from the C5 pivots, and ideally the C17 bush turned and faced true to the C13 shoe carrier.

The three C14 pins between each pair of springs transmit most of the drive, so special attention should be paid to their finish and fit in the C23 plate.

It’s OK to smear all rubbing surfaces with HMP grease, as only racers are likely to get the clutch really hot!

To get the C23 clutch plate to lift squarely, it is not necessary for all the springs to be the same length. It only needs opposite pairs of springs, when placed in their C30 cups, and installed in the plate, to be the same height from the face of the plate. However, it is necessary for the C15 spacers to be the same length, and to project slightly beyond the C14 pins.

 

[john998]

Hello, Just had the outfit out for the first run of the year. The clutch with longer centralising plungers and stronger springs working well. The gear change is also improved. Long may it last as I am too old for removing clutches whilst laying over the dual seat. John.

 

[Bill Thomas]

Yes John , My year started today too, The Sun is out but cold wind at Keyhaven on the coast.

 

[stu spalding]

If the shoe plungers do not contact their pins at rest, the simplest solution is to add 2 (hardened) rollers to the pins, rather than making new plungers, or boring out the housings.

Hi Mike, if the plungers are not hardened and it's only a matter of a few thou, try undercutting the collar on the end of the plunger. Cheers, Stu.