During my first dyno session with my Vaq back in May 2011 I experimented with creating another opening in the left a/b cover. I had already installed a K&N filter and saw about a 2 H.P. gain so that was a good thing. I cut open the round area within the label on that left side outer cover.
The skoot lost power, lotsa power. During the dyno run I felt air being pushed back OUT of the opening. HMMM..NOT GOOD!
We performed 3 successive dyno runs with that hole taped over by 1/3, 2/3 then fully taped over. Each run made up some of the power we had lost and when the hole was completely taped over our power was back to normal.
My next test was to remove the RIGHT side airbox cover completely and WALA...major power gains!!
Showed me how restrictive the stock intake system is to suppress intake noise. The triangular tube that connects the left and right airboxes is too restrictive to allow much larger quantities of air thru and creates what is called a sonic choke, where the airflow has lost it's velocity and just packs into that tube and can't get thru.
Bottom line, add a K&N to the stock airbox for a small gain in performance or go with a BAK and proper tuning. That set-up makes more power everywhere with no losses but as has been said there will be more intake noise.
"TRUE HAPPINESS IS IN THE HEART,NOT IN THE OUTSIDE FIXES!!"
WITH OVER 42 YEARS AS A MOTORCYCLE TECHNICIAN/HI-PO SHOP OWNER I AM A PURVEYOR OF FACT NOT FICTION!
"WE LIVE OUR LIVES IN CHAINS NEVER KNOWING WE HAD THE KEY"