There are three reasons why you want to remove the air injection system from your bike

1. If you are using your motorcycle on a closed course (racing, track days, etc.) you will want to remove all unnecessary equipment from your bike for reduced weight and ease of maintenance.
2. To get an accurate Air:Fuel (A/F) ratio when dynoing the bike. The air injection system pumps fresh air directly into the exhaust stream in order to burn off any unused fuel. Unfortunately by doing this the A/F ratio is thrown off by the extra "fresh air" in the exhaust stream. By removing the air injection system you can achieve an accurate A/F ratio.
3. This addition will typically remove the majority of popping on deceleration that can be experienced with un-burnt gasses within the emission charcoal chamber. Note: Proper tuning may be needed and this is general feedback.