Air Box Snorkel Foam
 

During re-assembly clean up of the air box lid, I noticed two smallish foam squares glued to the inside radius of the snorkel. I had not seen these before, or any mention of them in the forums. Being 26 year old foam, they were disintegrating. I'm not concerned about their removal, but does anyone have thoughts on what Mr. Honda put them there for? Intake sound damping?

What kind of Air Filter do you have? I believe if you have a K&N air filter, those areas are blocked off. I believe it is for venting the Diaphragms of the carbs through the air box.
I think that is what you are looking at.

It's not the "sub filters" that are in the bottom half of the air box. These were thin, roughly square pieces stuck to the inside of the snorkel. The snorkel (the only name I know it by) is the rubber piece that is attached to the air box lid that faces down between the top frame rails.

"Turbulance generators"?

That's what I was during my working career. So no, probably not.

Vortex shedding intake?

Velocity multipliers?

Definitely dB deadening to meet overall sound attenuation DOT limits...

That makes no sense. The sound gets sucked in on that end. Now, you're just making silly guesses, skokie.

Absolutely not, suppression of intake roar is as fundamental to meeting EPA and DOT noise standards as the exhaust system; as is adding sound deadening material to engine side, clutch, valve and countershaft covers.

Yamaha now has specially tuned intake systems that actually channel intake noise up through baffled sound ducts focused only up at the pilot to add to the visceral thrill of acceleration and decel. Otherwise the intake system is carefully dampened along with the exhaust.

Our VTR have the largest carbs Honda put on ANY vehicle, auto or bike. Those carbs make a huge racket going up and down the rev range. The foam on the underside of the fuel tank not only insulates the gas from heat but also dampens intake and top end noise. Air boxes are very robust and stiffened so they do not resonate unwanted intake and exhaust pulses that can set up a harmonic effect that upsets positive and negative intake pulses, and suppress unwanted sound emissions.

Don't believe me, just search for engine intake noise suppression and tuning.

The roar comes out the back end.

Again i'm trying to explain why the phone is in the air box only...:D

Was an airbox phone a factory option? Neither of my SuperHawks has one installed. You wouldn't be able to hear anyone over the roar in any case.