I confused... you have lost power to the lights, horn, starter,... but you say you have power to the headlight, but it don't light?...
If you have power to the light, but it don't light,.. the bulb is burned out...
If you don't have power to anything,.. check the fuses (use a meter, not yer' eyeballs)... check the battery connections, ground strap (behind engine clutch lever arm)..., stater relay connections(under seat)...
Check for voltage at the battery terminals... and double check your ignition key position...
Tell us what you find...
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