I don't know...I don't have an issue with my airbox lid noise, but I did something a little different. Maybe mine isn't as loud because I just opened the original hole a bit more while leaving some of the edges of the original lid. Perhaps this allows the sound waves to bounce around a bit more which may damp the sound a bit more. I don't run the snorkle.

 

I did a similar thing in my airbox -the larger KDX snorkel plus an extra intake hole that I cut out - not quite as large as yours but similar idea. It's a decent compromise of noise and performance.

 

I rode the bike about 35 miles today. It ran awesome with the lid off. I filled it up and will see what it gets for mileage on the first tank full. I do like it. If I went from full throttle to 3/4 really fast, it would bog for a second. Next is a 125 jet but not for at least one tank of gas. It runs pretty good the way it is.

David

 

This might have merit. Why not? Old pannty hose make good filters.

 

I've never noticed an increase in noise..

I go by performance first, looks/noise second

 

Why didnt you just remove it? Thats a BIG hole... i cant see that flowing less than removing the lid entirely.

 

Noise, then performance. Looks ? Huh? I don't want the noise so I do not attract attention to my self while driving like an idiot (hooligan). If I had a loud exhaust I would not hear the intake so much.

I took the lid off when I first got the bike. It ran like CRAP. I put it back on. This time with the NON CV carb and lid off it goes like a raped ape... Still going to try the 125 main. IF it runs good lid on, it will stay that way.

I noticed yesterday running around with the lid off, I could drop a gear and let the motor sing (scream?) a little and still be comfortable. It ran with power, but more like when it was a 250 with the power band more even. It seems everything I do to this bike makes for more low end power. It has enough, I want to find what is missing on the top end.

40% bigger = 40% more air needed at 9500 RPM. The inlet duct on the KDX snorkel is about as big as on some 2 or 3 liter CARS.

I do think removing the screen helped, but that is only with my butt dyno.

I am having a total blast messing with this bike. We have snow and wind again today. There she sits

 

Yes, a big hole...but...I think it still helps with some of that droning noise and water and debris will still have a harder time getting in with the seat on. With the lid completely off, it's kind of like a big, open, empty, coffee can...easier for things to fall or pour in...also maybe more of a megaphone for sound. This opening is more akin to a large bottle with a necked down opening. More airflow than stock and probably more area than absolutely needed, but the lid still probably aids sound resonance and can't hurt with water trying to lap/spash in. Nope...no dyno charts, no NASA decibel tests, and no U.S. Navy submarine testing...but it didn't cost anything.