http://www.dpguzzi.com/relay.htm
Smaller and cheaper.
+pos goes to 30
low beam wire to headlight to 87a
hi beam wire to headlight to 87
hi beam wire from handlebar switch to 86
-neg to 85
In the non-energized state 87a has power so the the power feeding the relay at 30 needs to be switched but in most applications it is.
So when using low beam the relay is actually not energized but passing power to low beam through 87a. When energized it passes power to high beam.
