Wireing help

[vivabird]

Can any one help identify this wireing ? Viva HC 1972 Was in the process of being upgraded to a larger engine but was never completed by previous owner. Now has a 1256 engine abt 1979 the head light wireing,indicator and horn are already accounted for. can anyone tell me what this other wireing is please.

Thanks

[viva power]

[1256man]

hello purple and black wire is the horn normally the green and white goes to the indicator normally