Hollow sound near carbs

I put on the new intake boots and air-side boots I got from Z1Enterprises; it was much easier to install the carbs as the new air-side boots were soft enough so I could fold them back on themselves, making more room to slide in the carbs. I cleaned the carbs while they were off.

The bike starts, idles, and runs great, plugs are light coco brown, but it seems to sound different; it has a hollow sound which seems to come from the carbs, maybe nearest the float bowl area, but it's hard to tell. The attached wav file has the sound; there's a lot of mechanical noise in the recording too, but that has always been there; it's the hollow sound that seems new.

I'm wondering if the new air-side boots are made of a thinner material and causing the noise. The sound is almost like I'm running K&N air cleaner pods, but it's all stock (stock air box and filter; I changed the air filter but that didn't change the noise). Any thoughts?

did you put any sealer on boots when you mounted them to head? maybe retighten everything

Make sure all nipples on carb holders are plugged!

I did use sealer on the intake boots; squirted everything with wd-40 while running to see if there were any leaks, found none. And there are no ports to plug on the boots. This is weird.

if you have a propane torch handy just crack the valve open where you can just smell propane without lighing the torch and run it around the carb boot area and around the carbs with motor running,if youve got a vacuam leak it will let ya know

Thanks; I'll give it a try tomorrow and let you know; I'm not sure wd40 would tell me and I don't want to use carb cleaner on my new boots.

In a unrelated matter, today while in traffic my petcock vacuum valve started pissing out gasoline (a steady stream); I made a temporary road-side fix and need to order a new one.

Used the propane torch idea to check for intake/vacuum leaks and found none. The bike kept the same RPM. But the bike's running fine, so I guess I'll just ride.