Lacking any other data I have to assume that the racing association, which allows people to ride motorcycles at speeds of like 200mph around tracks is nervous about being associated with a dangerous product like cigarettes.
Don't think Camel, the GP folks, FIM or Yamaha have squat to do with it! It's a government thing! What's the point of sponsoring something when over half the countries raced in don't allow tobacco advertising! Those big blank spots on the bikes (and F1 cars for that matter) are worth big, big bucks and get big time exposure. Might as well be purchased by someone who can actually use them! May be Guinness or Jack Daniels are available...and that is ok for most of those same governments, go figure...
The story is simple. In many GP rounds the tobaco maker logo has to be hidden already and it's only getting worse. Seemingly Marlboro will have only their colors on the Ducati's as clue to who's the sponsor. So the publicity return for the odd 10 millions $ Camel were supposed to shell out would have been very small.
Make sense to me. Now if I posted this comment. Seruzaweasel would of said something about speed doesn't kill and cruisers have better brakes than sportbikes. longride would of called me a liar. And Buz would made a sarcastic comment but it would haven been at least funny.
For you single fellows, Spanx be footless pantyhose. The gal who developed them was featured here on ATL TV show honoring young, successful entrepreneurs ( she is on the tasty side, too). But I digress...
I could tell a long story about meeting an owner of a dying hosiery mill in N. Central NC who went on a rant about Spanx - too much trouble to mfg and sell a hot, new profitable product. (??!!) But I won't. I think that fellow owns a new gen Indian, too.
Yamaha apparently doesn't want to be associated with a "drug" company. Can't blame them. Not that motorcycling isn't any less addicting, but at least one can participate in the activity of owning and riding without acquiring the health risks and horrible death that comes with cancer; lung, bladder, etc. Seen men die from it; ain't nice stuff.