Honda-SOHC

Still in the process of rewiring my bike, most of the old wiring was beyond redemption so new loom and handlebar controls. It all went together pretty easily, just some non-standard wire colours from the R/H control had me scratching my head, call to Dave Silver got that sorted. It is the horn that i find confusing, 2 leads from horn, one Lt Green attaches to the loom, easy, the other lead from the horn is Black which then seems to then morph into Green. The black lead has a male bullet connector on the horn sub loom, can't find where it should connect to, as its green can i just earth it somewhere suitable. A lot of fuss over a humble horn, but i want to get it right. Thanks in anticipation.