I've been giving serious thought to doing this. One thing I've noticed is that it's completely impossible to completely synchronize the carburetors. If you synchronize the carbs at idle, they are off a good bit at 4,000 rpm. And if you synchronize them at 4,000rpm, they're way off at idle.
I just happen to have a spare airbox (and a spare snorkle), so I'll probably do this and re-synchronize the carbs. I'll post my results when done.
Peace.
-CCinC

 

That seemed completely unreasonable asI assumed the pressure drop in the carb was dependent on the amount of air flowing through the engine, but I suppose that is regulated at the airbox opening so it does sound plausible but I do have my doubts. I'd like to hear your results, gotta have the CCinC seal of approval

 

i did this mod on my bike i didnt notice any more power of any kind...all i did notice is i can hear the air puffing thru the hole at an idle, abd the bike is a bit louder sounding...but as far as any performance mod...i suppose it does get a little more air this way

 

I'm not looking for any power gain, just balance.
It's certainly plausible that the reason it's so hard to synchronize the carburetors perfectly is because the intake snorkle is pointing almost directly toward the left carb intake.
And since I've got an extra intake snorkle laying around, I'll insert that into the new hole. That should dampen some of the intake noise.
Stay tuned...
-CCinC

 

and for some reason, I was thinking about addinganother horn to the newly drilled hole in the airbox. Just thinking aloud, still trying to see the whole picture.