I had one of the little plastic lugs that push into the rubber grommets break off when I was inspecting the air filter the last time. That pesky one that at the very front corner above the headlights.
The lug itself was lost as well for good measure.
I fixed this as I do most of my plastic fixes.
I drill a hole into both sides and used a copper wire to join them, and then use a liberal amount of araldite. Make sure it is well cured before reassembly.
In cracks, I will use the wire like stitches from the back side, and also use a dremel to grind out a little groove for each piece of wire.
I have also used this technique with plastic welding with a soldering iron. Also works well but it is useful to have some doner plastic around.
Hope this helps out.
Why drive when you can ride!