And it goes like this, mother Honda has planned it that way......What you say? Now bare with me on this as I tell you about something that has happened to a good friend of mine called Dale. Now Dale owns a small local boat sales and marine supply biz, he sells about 25 expensive ski boats a year along with other boats(the brand don't matter).
Now every time he sells one of these ski boats he has to install a drain plug in the rear transom at his expense, the boat manufacture does not supply the drain plug. Now this has been going on for some years and one day he is at the ski boat manufacture's plant and has a chance to talk to the owner of the company and politely ask him why the manufacture can't supply this $5.00 drain plug since he does buy 25 of these expensive ski boat each year and it would be cheap to do so. Here is what the boat manufacture told him, "you sell your 25 boats a year and I sell 7,500 boats a year around the world so it would cost me $37,500 in drain plugs while it cost you $125 for your 25 drain plugs and with the $37,500 I save by not supplying the drain plugs I give my employees a weekend vacation in Hawaii every year".

Now what does this has to do with Honda shorting the oil in the rear diff? Well look at it this way, if Honda shorts each rear diff 2 oz of oil on (a number I came up with for all shaft driven MC Honda makes and sells in north America) approximately 250,000 shaft driven MC each year around the world, that is a savings of 7,812.5 gallons of rear diff oil not needed. Now if Honda's initial "check list" includes checking the rear diff and every dealer is checking the rear diff and topping it off upon the initial set up Honda is saving a lot of money in rear diff oil and passing the cost off to the dealers, which is a very small amount to the dealers(2 oz per bike).

Yea, I know this sounds like a big conspiracy theory on Hondas part with Honda figuring the dealers will catch it and top them off, but then the dealers, trying to cut corners on "set up" time & charges are skipping this step? We the ultimate consumer are paying the price.........
I mean why else are we seeing so many rear diff a few oz. low? I wonder if the same thing is being seen on other models of shaft driven/rear diff Hondas? Oh and by the way mine was full to the top, but I bought it from a H-D/Honda dealer who knows how to check for low oil
Food for thought.