Stripped plastic threads - Air filter cover

[Shifu]

You need to go easy on them. There are a lot of screws on busa that are going into plastic. Carefull with bigger screws as they might crack the hole posts. Once that happen there is little you can do and it can be expensive to replace it. Suggest a screwdriver with a pre-set torque to avoid overtightening that might also deform the parts and affect their functionality.
Another trick when re-assembling plactics is to find the orinal groves cut by the screw previously. Just gently rotate the screw without any pressure. It will find it. Otherwise cutting the new groves every time will eventually chew up all the available material there.
Dirty air filter should really be replaced rather than cleaned too. Hope my suggestions helps for the future.

Cheers