WHAT IS THE AIR FLAPPER MOD AND HOW DO YOU DO IT?

 

https://cbrforum.com/m_164508/tm.htm same post below

 

Don't bother. There is no real horsepower gains from it. All the flapper does is open half way in teh low revs to limit airbox noise. The bike will only suck in so much air at a time, and increasing it in the low revs will not increase your power.

I tried it both ways, and it made no difference at all. Everything I have read says the same thing.