Originally Posted by plodalong
Just checked the ones I took out and they are 5mm by 15mm long standard metric thread (looks like .8mm pitch or 12.5 threads /cm) Have fun, you need to take the clutch out or it will be a lot harder if not impossible.
You don't have to remove the clutch assy, I just did it today, takes a little patience to unscrew the back one, here's what I did:
With the bike laying down,
Sharpened a punch and bump it into the screw head in the loosening direction, it came loose pretty easy, once it was loose I used a magnetized screwdriver to continue to unscrew it until it was out
I kept the front screw in because there seems to be a spring under the unit,... I changed it to the allen after the back one was in
Put the allen screw in with long nose pliers and use a ball tip allen wrench 1 size small for the extra play to easily screw it down into place then tightened it with the correct size
The factory screws are 5mm x 15mm x .8 pitch, but I replaced them with 5mm x 20mm x .8 Allens so I could shim up the head, If you look close you can see two 5mm washers under each allen head.
This is so the holes used to run the wire through clear the top of the NSU unit itself otherwise it sits below and it would be a hassle to get the wire around
You need long nose pliers to do the wire work,...
Stuff a paper towel in the hole below the work so nothing falls into the motor (not shown)
I was ready to take the clutch assy out until I saw someone a few pages back do it this way...