Well, I finally got the FT-7800 installed on the bike. The small interface box on the rear side has a toggle switch to switch between the helmet headset and the hand mic (with front speakers active). Speakers are MH Instruments "Rumble Road" type. The jack next to the switch is for the mic plug. The two 6-pin mini-DIN jacks are for helmet headsets. I have two different configurations provided (several helmets). There is also a .35 audio jack below the switch to patch radio audio into the "chatterbox" helmet to helmet intercom. I initially had some "desense" of the microphone input circuit in the radio until I placed clamp on ferrite chokes at strategic places. This showed up as reduced TX audio at high power on VHF. I shielded the lines from the control head in RG8 braid (inside the flexible sheathing that bundles the lines). It's grounded to the frame.The antenna bracket and PTT switch bracket are modified from GoldWing brackets supplied by MARC. The antenna is a Comet SBB-5. The installation works well on both bands.