You need to grease the clutch bearings every 600 miles, see how it's done.
http://www.mabecanemobylette.com/greasing.htm

how much is too much for greasing the dimoby clutch? like one pump? two? thanks

If you use a large cartridge grease gun then one pump should be enough to regularly service the clutch. The centrifugal force will chase out the extra as long as it is not a huge amount of extra. If it become over greased and you have oily gunk coming out of the clutch casing and it slipps like crazy or grabs harshly you can use brake cleaner to remove the excess grease.
If you do not have a grease gun you could always get a chainsaw grease gun from the hardware store.

If your moby has just been salvaged from it's seeping place, where it's been for the last 20 years, the grease in the channels after the grease-nipples will be dried out and you will not get any fresh grease in. you'll know, when all the grease comes out fom the side of the greasepump's snout. There's nothing to be done than take off the clutch/ vario or the large pulley and clean those channels out. Take off the grease nipple and go through the channel with some steel wire. Then flush with WD40 (use the straw, to get deep insde). Best would be to blast through with compressed air. Fill the channel with grease (press it in with your finger, until it comes out through the side of the axle). While you're at it, clean the inside and bearings of the clutch/vario or large pulley. put fresh grease in and replace. You're set for the next 600 km.

Nipples
There are four basic sizes used on the Mobylettes - 4mm 5mm 6mm and countersunk.
4mm ones have a 6mm hex to remove and the threads are 4x0,75
5mm ones have a 6mm hex to remove and the threads are 5x0,75
6mm ones have a 8mm hex to remove and the threads are 6x0,75
The countersunk is the one mounted into the pedalshaft and is flush with the end of the shaft with just a brass ring and ball showing.

Late model Mobylettes use 6x0,70 threads.