[DaBlue1]

This info may save you a lot of work and frustration, but to answer your question as simply as possible. Leaving the airbox in with stock jetting and carb setting and a full exhaust, make close to 30 HP. The average of 2 shims under the needles, snorkel removed from the stock airbox and a slip on exhaust can make up to 28.5 HP. Stock airbox removal requires larger main jets. 87 octane works better (non ethanol if you can get it).

Leave the airbox in???
http://www.ninjette.org/forums/showthread.php?t=124144

Wide band A/F Gauge
http://www.ninjette.org/forums/showthread.php?t=67530

How Constant Velocity Carburetors Work
http://www.motorcycleproject.com/mot...bs_work_v3.swf

Motorcycle Carburetor Theory 101
http://www.motorcyclecarbs.com/carbs101.pdf

Pipe Jetting (A Must Read)
http://www.motorcycleproject.com/mot...s-jetting.html

Carburetor Jet Tech
http://www.motorcycleproject.com/mot...et_tech_v3.swf

Resonant Airboxes: Theory and Applications
http://motorcycleinfo.calsci.com/Airboxes.html

Jetting Database
http://www.ninjette.org/forums/showthread.php?t=10208

Stock 2009 Ninja 250R Dyno Chart
http://www.ninja250mods.com/Ninja-20...Ninja-250r.jpg