I recently purchased a 1979 GL1000 and need to replace the throttle cable and clutch cable. In its history 3'' risers have been installed. Will the OEM cables fit and if not what do I need to find?

Best bet is to take the old cables off, measure them and take to a dealer to find replacements based on length. Sometimes the OEM have enough slack in them to compensate for the risers, but many times they required a longer cable.