Removing the alternator on a 4 valve K100
By MT350Explorer

Not a technical job and one well described in manuals but often a few photos help, especially for relative newcomers to the 'K' (like myself). 2 valve procedure is similar: the alternator fixings are the same. Also see Crazy Frogs post in this section which refers to replacing the bushes etc.

Before: picture of (unplugged) Motronic units (silver box) and ABS unit (black, right).

Below, Motronic and ABS units removed (allen keys - simple); battery and battery tray removed (nuts and bolts and a wiring connector or two- also simple). Battery tray had to come out to get access to the 3 allen bolts seccuring the alternator. Pull the power lead straight out of the back of the alternator

Below the alternator connector. This is one area of the bike I had not visited before and with corrosion like this it was a miracle the alternator was working! Some contact cleaner and a toothbrush worked wonders

Below, it would be a difficult job to undo the two allen bolts securing the alternator that are inside the bike without an allen head socket attachment as they are well recessed and hard to move. I used a 3/8" drive with extension and the bolts came out no problem. There is a third bolt outside the bike beneath the plastic cover that is much more accessible.

Below, is the alternator once extracted showing the 'monkey nuts' - 3 sets of two rubber cushions that damp vibration from the alternator. to my eye these looked OK: they had worn evenly and were not broken. The bike also had the same level of vibes with the alternator in or out.

Finally, here is a pair of 'simian testicles' removed from the alternator but showing them the correct way up to go in.

Then stick it all back together!

Hope this is helpful