Clutch Specifications: R 68

[Philip Vergison]

I'm in the proccess of having the clutch serviced as part of a closer examination of the motor of my R68. Can anyone advise what the thickness of the clutch friction plate for this machine should be? The existing plate is just under 4mm thick.
Thanks in advance.

[Geoff Curtis]

Marks parts list has 7mm & 9mm plates listed , my 1954 R68 has 7mm plate. Regards ,Geoff in OZ.

[Allan Atherton]

I heard the original 9mm plate feels much better, so it is what I bought for a spare part. It has a layer of curved pieces of steel sandwiched between the two friction surfaces. These pieces give a sprung action to the engagement, eliminating any unevenness in the initial contact. It appears that if one sector of the disk were to maake contact before the other, that side would compress until the whole disk made contact.

I know of one person who bought the cheaper 7mm disk, and found that it did not work as well as they expected, so they soon replaced it with the 9mm disk.

Here is a photo of the9mm "sprung" clutch, also showing the little slinger on the engine side that throws off any oil coming from a leaky rear engine seal.