I want to put mesh grills on my fairing vents
From Ninja250Wiki
The standard material for this modification is gutter guard from Home Depot. This is the mesh that is used to cover home gutters and keep leaves out.
The project featured here used automotive grill material from an Auto Zone-type accessories store. It comes in a big, flat sheet and is a little more expensive than the gutter guard, but is also much stronger.
If you can't find something you like locally, Grille Guy will sell you some.
You cut the mesh to size with tin snips, then paint, if so desired. Use 3M car molding tape to attach the pieces. You can even manage to do it without taking off the front fairing if you have itty bitty hands.
Shown below is the same modification, using gutter guard and 3M double-sided tape.
