But unfortunately, Yamiya carries nothing specific to the 750F's, and a 75F requires a very specific harness. It has a separate connection case that moves many of the connections made in the bucket to a small plastic case on the front of the frame opposite the horn. Substitutions, repairs, and work arounds are very tricky to do.
From what I have seen, buying motorcycle parts on Amazon is a big crap shoot, much worse than Ebay. If you cannot find a new/repro harness for a 75 750f from a reputable seller, than I would try and find a clean used harness.