I am so appreciative of this site and all who contribute! I am looking foward to getting a 1978 xs400 up and running by spring. Who knows how many years it wasnt running for and where it would end up if I didnt get so excited about it? I went over almost every one of these schematics as well as the bikes actual wires to debate changing the whole harness or just adding another wire to the rest of the harness to (temporarily) handle that issue. I went through the trouble of translating the german schematic,getting a wire colour code from the manual, tracing the connections. I am not sure how accurate this will be for anything outside of my '78. I compiled this list with the intention of a electrical troubleshooting short cut. Its handy to have the colour coded schem hanging around but with my list all you need infront of you is your bike, and a good parts compass.
I Tried not to be too cryptic so make changes, corrections, or edit info as it suits you.
Colour Codes for wiring (and parts) of a 1978 Yahama XS400 (E)
B..............Black -All Lights, Tach + Spedo(no indicator lights), Battery Ground, Blinker + Horn Switches, Rectifier, Voltage Regulator, Blinker Off Circut
Br...........Brown -Oil + Neutral Indicator Lights to (Horn)(Voltage Regulator/Alternator) (Brakes) (Flasher Relay) (Blinker off circut) (Ignition Lock) (3x 10A Accessory Fuse wired here.There is a single Brown wire connected to 2 Brown and 1 Red/White wires of each of the 3 fuse ends. The other side of Each Fuse will have 2 Red/White wires and 1 brown wire connected.{opposite})
G.........Green -Alternator to Voltage Regulator
L.........Blue -Spedo to Tach & Ignition to Light Sw
-Tail Light to Ignition Switch
O....... Orange -Capacitor/Contact Breaker/Ignition Coil
P.........Pink -Horn to Horn momentary button
R.........Red -Ignition to (20A Fuse/Batt)+(Rectifier)
C........Chocolate -L Indicator Lights(3) to Switch
W.......White -Alternator To Rectifier
Y........Yellow -Brake To Rear Brake Light
-Alternator to Headlight saftey Relay
Dg.....Dark Green -R Indicator Lights(3) to Switch
Gy......Grey -Capicitor/Contact Breaker/Ignition Coil
Sb.....Sky Blue -Neutral (clutch) to Indicator Light
B/R....Black/Red -Oil Pressure (Alt) to Indicator Light
G/Y....Green/Yellow-Front Brake to yellow wire of rear brake
L/G.....Blue/Green -Lightswitch On/Off to Hi/Low Beam Sw
L/W.....Blue/White -Starter Relay to Starter Mom Button
R/W....Red/White -killswitch to 10A Fuse (series)
-Ignition coil to starter relay/killswitch
-Headlight Saftey relay to Fuse
R/Y.....Red/Yellow -Lightswitch to Fuse
W/G....White/Green-Blinker Off Circut to Reed Contact
Y/G....Yellow/Green-Flasher Relay to Blinker Off Circut
Y/R.....Yellow/Red -Blinker Switch to Blinker Off Circut
Br/W..Brown/White -Flasher Relay to Blinker toggle Switch
L/B.....Blue Black -Headlight saftey relay to Headlight
Off Harness wires that are needed
Y.........Yellow -Beam indicator/spotlight/Hi/Low Switch
Lg......Light Green -Headlight to Hi/Low Switch
L/G ....Blue Green -Light s/w On/Off to Hi/Low s/w (maybe different colour)