So I modded my air box, documented in my "de-snorkification" post. I bought a very cheap e-bay second air box to do this mod, because I was unsure I would like it. I like it. :-)

I have searched on this subject here and elsewhere, and talked to Martin (aka Marthy) about theories on why Yamaha has two short stacks on the outside and two long stacks on the inside positions within the air box. A reasonable theory in general is long stacks help mid range and short stacks help top end, so Yamaha split them up to get the best of both worlds. I have a hard time buying into that, as having the outside cylinders intake properties being different than the inside ones just doesn't make a lot of sense to me unless someone can explain that reasoning better. Some have suggested it's due to the outside edge of the airbox top tapering down to accommodate the thank tilting down on top of it. Maybe. My theory is it has more to do with the OEM tall snorkel, that from car experience I believe was engineered more to reduce intake noise else than anything else, along with their estimates on just how much air the intake runners actual need.

With the snorkel cut out, and having two boxes making it sort of easy to try different stack length combinations, I am thinking about trying all long stacks for better midrange. I have seen some posts including Martin's input that going all short gave a perceived better top end response. The only thing I found anywhere on going all long was on a 'Busa forum. They have the same short and long stack combo as us stock. There was actually a post with beforehand and after Dyno graphs going to all stock long stacks. There was a distinct midrange advantage.

Has anyone tried this on our bikes? Any thoughts? I still have a timing advance mod and front sprocket change to try each separately before I try anything with the stacks, just curious what input I might get here.