id stick the
two red to +ve battery
two green to -ve Battery
and cross your fingers
on the old set-up id guess at the single red and the red with black line being a longer way back to the battery errm perhaps with a fuse in there
and you wont get a battery light on the dash for the battery being dead any more
sounds like you have a slightly different reg/rec to the one I've recently got for me 92 750 SS again a 2 yellow wire version i got that from electrex world (via a main dealer) and that's a RR51