I am a little bit lost in connecting new H 4 socket. I have to connect it properly but after cut od wires I am confused: Which wire goes to left side of socket, which goes up in the middle, which goes to to right, looking from behind. Instalation is from early K 100. Three wires: grey green, black red, grey red
Thanks in advance

@nino wrote:Three wires: grey green, black red, grey red
Thanks in advance

These colours is not OEM, and not after the DIN standard which is used.

@nino wrote: Which wire goes to left side of socket, which goes up in the middle, which goes to to right, looking from behind.

Left: Brown...ground, middle: yellow...low beam, right: white...high beam.

Have relays been fitted Nino that may explain the different colours.
The wires should be Brown for earth/ground  White for Hi Beam and Yellow for Lo beam.

Thanks problem solved. I am not aware of any headlight relay on bike. if there is one must be in relay box.

You will need a voltmeter/multimeter or alternatively, a 12 volt bulb in a socket with two flying leads.

Look at the back of the new socket: the red wire is earth (!!!), the yellow wire is dip beam and the blue wire is high beam.

With a voltmeter, on the bike:-

1. Turn the lights on to dip beam
2. Check for voltage on all three wires. Whichever colour has 12 volts on it is the dip beam - connect to the yellow wire on the socket
3. Turn on high beam. Again, check for 12 volts. Whichever colour has 12 volts on it is the high beam - connect to the blue wire on the socket
4. The 'other' wire is earth - connect it to the red wire on the socket.

If you only have a bulb for a tester, do the same as above but earth one side of the bulb to the bike. If the bulb lights, you have 12 volts on that wire.

Here is a typical H4 socket:

Thanks, problem solved. With new voltage regulator H 4 looks brighter