Here is the headlight relay circuit from the 92 CBR 1000f manual. I have tried to highlight the circuits using the penultimate app, fat finger and shaky Blue is the battery supply Red is the low beam control circuit Yellow is the high beam control circuit
As you can see Mr Honda has decided to improve the headlight circuit by taking all the power away from the headlight switch, flash switch and ignition switch by using relays with the power coming from a fused battery circuit. :Egyptian:
The main reason is that there is hardly any copper left in the wiring and it can't handle high current as well. Also the shorter the circuit without breaks ( switches, plugs etc) the less voltage drop.
Ansimp - stumbled onto your thread regarding headlight relay. Have read similar threads elsewhere and installing relays and powering the headlight with relays for better power delivery is now quite common but not back a while with our bikes. Have found a circuit as well on the net regarding this:
This schematic is for dual low/high installs. Easy to downsize for single high/low install.
Agree with the issue of lots of relays, but the benefit is there regarding the older electrical systems, and relays are very common place. Just have to be selective in relay placement, type and size of relay and how the circuits are fused - additional fuse block is a good consideration. Make sure that with any relay install try to keep relays the same - micro/mini - and have spares with you in case.