Buy a DIN socket like
this (thanks BHT) and some 20 amp cable and an in-line fuse holder that will take a 15 ampere fuse.
Mount the socket securely in a convenient location.
Take a length of the cable and fix (preferably solder) a spade connector to one end. Attach the spade connector to the spade on the socket that links to the OUTER part of the socket. At the other end of the wire fix a ring tag connector and find a suitable point to attach to the metal part of the bike.
Using another length of cable, attach another spade connector with an insulating sleeve. This connects to the other terminal on the socket. Route the cable to the battery avoiding hot areas. Cable tie both wires so that they don't chafe against any part of the bike.
As near the battery as possible, attach the fuse to the cable. Ensure that the connections are all well insulated and that the fuse is located where it can be easily changed. The wire from the fuse connects with a ring tab to the +ve terminal of the battery.
Done!
Greg
