The Flapper Mod
The flapper is there for noise restriction reasons. My bike has a sticker on it stating it makes 88dba at 5250 rpm and of course at this point the flapper door is closed to make the bike quieter. Un plugging the flapper doesn’t make a lot of difference because most of the time the door is open. So there is little to worry about disabling the flapper to ensure it’s open all the time because most of the time it’s open anyway.



The Snorkel Mod
The snorkel is also a noise restriction device, when the flapper door is close all the air entering the air box must travel up the snorkel and therefore is quieter due to it’s length and it’s ports pointing towards the ground. You can simply pull the snorkel out which will make the bike significantly louder. When the flapper door is open the snorkel provides a small restriction which is why dynos prove a less than 1hp gain across the rev range when the snorkel has been removed.



Once I made my own air filter I found the bike to be mind blowingly loud at WOT and put the Snorkel back on. At idle replacing the snorkel reduced the dba’s by 10 !

http://www.vfrdiscussion.com/forum/inde ... rack-bike/
http://johnny.chadda.se/article/pair-an ... d-for-vfr/