As a learned from another post (forget the username name for giving credit):

Steps:

- Rotate the needle to full stop. You will see the needle stops about over the km on the km/hr stamp. Rememeber this to reset the needle.

- release the needle so it goes back to 0 and rests on the stop pin.

- (this is the part that is scary). Left up the end of the needle over the stop pin so that it clears the pin while rotating the needle counter CW.

- Keep going Counter CW until the needle finds its internal stop. Gentle keep going to release the needle base grip on the speedo center mast pin.

- once it releases, gently pull the needle straight off while turning it counterCW

- you many need to go over the stop pin again. Just lift the needle over it again.

- the stop pin is fragile, so be careful

- to put it back on, slightly reinstall the needle on the speedo mast pin (enough for a gentle fit). Rotate needle clockwise until the needle stops over the km mark (remember) - and then push the needle base down on the center mast pin to keep it in place during final use.

- try not to touch the gauge surface. it doesn't like greasy hands

I have no comment/experience on the voltage gauge - sorry. It would be nice to have one though. My 86 745T has one (but that is my X wifes now!)