10-12-13, 11:31 AM
There are sensible and stupid ways of modifying the headlights.
Done correctly the dip filament on the right goes off when the high beam filament is lit. If the feed for the dip filament is taken directly from the H1 on the left it means both the H4 filaments are lit when you select high beam. This overloads the wiring and fuse and the extra heat cooks the coating off the reflector.
Look under "Articles"/"FZS600" to find the thread describing the correct way to get dipped beam from the H4 bulb.
The rev counter issue is a new one on me. As a starting point I'd check all the connectors in the black box under the tank. Make sure all are clean and the contacts tight. In particular look for any that have green corrosion or signs of overheating. Also check the connector on the back of the instrument panel.