I finally got my tach off the bike and the lamps changed. The disconnect plug is under the headlamp, The bulb sockets must be pried out and then you just pull the lamps straight out. I oiled the tach and put the new lamps in. The tach is still sluggish below 2500 but works fine above that. So, now I know how. The Z750 is a fairly simple machine to work on...hawken...