Air filter being clogged would tend to cause a rich condition (i.e. less air getting through, not a lean one).
If spraying around the boots caused your revs to change, that's 99.999% surely your problem, those should be sealed, spraying there and seeing revs change means you have a leak. People always try putting that silicone stuff on those when they start leaking, and it never seems to hold. If air's getting in there, what happens is your engine pulls the same amount of air, but since it isn't all going through the carbs, they lose some vacuum, and don't get enough fuel in, thus causing the lean condition (i.e. too much air, not enough fuel).
I asked about the filter, because a lot of times guys switch to a high flow air filter, or just take the filter out, and have this kind of problem. I'd check out Z1 enterprises for some new carb holders (the boots between the engine and carbs), and maybe some new boots for between the carbs and airbox too if those are old and crusty, they should be nice and soft.