It should run down to the motor itself. It gets sandwiched between the lower right top mount and the engine casting .....
It may originally have been insurance for the condenser pack grounding. Honestly, I can't say for sure why Yamaha did it, but I always leave it in place. It's still there even though I run a Pamco now.
Ditto, that's how my unmolested '74 with points was done before I took a sawzall to it. Also, one of the unmolested top motor mounts was broken.
Scott