thats not an antanna! thats the starter interlock box, it connects to stuff like the clutch and sidestand switch and desides if it's safe to start etc. I have 1 or 2 working units left over if you can cancell the ordered part still. will go for peanuts if your interrested!
Make sure that you have the right contact lock and the key antenna ring that fits around the lock though! you need that to communicate with your digital key's.
999 LC8 Rat-Rally custom - 500 EXC - XR666R '85