So did Ducati bend that stack or was it your modification? I have to remove the clamp on my carb in order to get enough clearance to remove the stack. Anyway, it's my intention to try and fit air filters for some street riding even though the stacks are more appropriate.
But I was curious to see how the other F1 "specials" dealt with the problem. Love the fact Ducati would crimp or cut into a frame tube to clear a carb.

When I took delivery (new) in early '86 it was immediately clear that there was a serious clash between bellmouth and frame, so I marked the bellmouth, removed carb assembly and (carefully) clamped it in the vice and delivered the "mods" to the bellmouth with a suitably sized round bar and hammer! Sounds a bit crude but it was easier than expected. Fitting the bellmouth to an old carb body for clamping in the vice would have been a better idea but didn't have one to hand - so I was very careful instead. It would be interesting to know if the Factory ever addressed this problem for the Montjuich later in its production run as mine was probably the earliest "customer" bike, so not everything fully resolved by the time it got to me.
Regarding wire mesh verses filter - the mesh bellmouths have always been fitted on my bike without any issues but, admittedly I have used the bike sparingly (9000Kms). I live near the coast so I'm careful not to use the bike when there is any chance of sand blowing around. Hope you get things sorted - Richie.

I thought of this thread yesterday when I was putting a vertical cylinder carb on a TT2. Long float bowl nut and rigid, bevel style intakes. Bolt carb to intake, bolt intake to head. Now you will find out why they cut a hole in the fiberglass shock surround. It still isn't easy, but it will fit. Now make sure the carb top isn't hitting the shock spring! Jeez everything is so close on these bikes. Variations on horizontal intakes and frame clearance as well. Lou