That's because you have a very pie-in-the-sky view on the capabilities of a, relatively simple, motorcycle efi system. The computer WILL adjust the afr but what it WON'T do is take any given point/points on the fueling table and adjust it to anywhere between 0-100% injector duty cycle. It will take the pre-programmed pulse width and adjust it up to a programmed maximum percentage to try and maintain the (far too lean) EPA friendly afr. They can, and will, run out of adjustment range if too drastic a change is required, though an air filter alone is highly unlikely to reach that point. It should have been blantently obvious 50% was pulled out of the air to illustrate that LARGE changes would be problematic.

Besides that, some systems will adjust the ENTIRE fuel table, or portions of it, as one big block instead of individual cells of the table. Because some mods (especially exhaust) affect different points on the a/f curve differently a tune IS required because the bike computer does not have a fine enough resolution in it's adjustment to actually change the curve as is required to get a good afr over the ENTIRE operating range.

 

I can tell you my bike, sans tuner, is detonating and there is evidence of this in a new pair of spark plugs with 500 miles. There's also the issue of popping on deceleration. The bike's computer doesn't seem to compensate for these issues.

 

Just for an Air intake....


YES.... it will be OK>>