After reading all the posts on how this bike wants more air, and runs rich from the factory, I had an idea that someone here will probably be able to tell me won't work. I looks like with just the seat off, you can access the back of the air filter box. What would happen if you cut a hole, of whatever size, and managed to fasten generic flat air filter foam? Here is what I have found: http://www.motorcycle-superstore.com/32 ... ilter-foam.
That should increase the air coming in without messing with the snorkels, as well as being protected from most water intrusion. You also wouldn't have to take the tank off, and if the piece of plastic cut out was saved, it could always be glued back on later.
This should lean the mixture, depending upon how large the hole is cut, and therefore the amount of increased air flow. The right sized hole could put the mixture closer to optimum, without any other expense.

Why won't this work? I m getting mine dynoed next week, and will see how it does over stock both in torque increase and fuel mixture.

Well I just looked, and you can't even see the airbox with the seat removed, it takes removing the gas tank. If I took the tank off, I think the best thing would be to drill holes across the top of the box, and cover them with one piece of the filter foam. Then you could just duct tape it down, since the air flow is going to keep it stuck to the outside. It should do like the Rottweiler box with the air filter replacing the top of the box. When I dyno it, I will have him take to top off, and see what it does to torque and mixture. Maybe there is a dyno chart here that shows that, but I couldn't find it.

Comrade: Have a look at Kev's (kevxtx) posts and/or his web site. He's done a fair bit of thinking and modifying in this area.

Can't wait to hear what a motobox does for the 1290. If it has a similar effect as on the 990 you guys are going to love it!