I gather that it's a 600, but what year? Off hand it looks like someone has been putting fiberglass where the rear upper fender and/or fender cover was, and has generally messed up the wiring. Is that black rectangular thing a resistor and is it associated with LED turn signals? I'll guess the the original wiring was around the compartment's edges and you now have a mess to deal with. Can any of those wires be relocated? What is this chain that you mention?