2012 Air Box Filter Mating Surface
 

I noticed on my 2012 300 that I am getting dust past the filter in spite of heavy greasing of the filter/Air box junction. I looked closely and see that the spongy air box mating surface is no longer flat (I assume it was at one time). It is depressed in toward the carb in two spots.

Has anyone else noticed this problem and is what is the recommended fix (aside from new air box)?

I'm thinking I can add a spongy seal layer to the air box lip that would compress more in the high spots and less in the low areas thereby creating a better seal.

Thanks

PC Racing makes a neoprene ring that applies to the airbox mouth. The neoprene has some give to it to help correct surface flatness irregularities and also makes the overall spring force greater. I've used them with positive results on everything from Yamahas to GasGas' and have them in stock for the Spanish bikes.

I got mine replaced as it was not sitting well and start to laminate also.

So far so good here....touch wood.
Cheers Mark:D

If you look closely at the '07+ filter/cage/boot design, you will see that it does not depend on the flat surface for a seal. It seals on the inside edge of the boot where the foam is pinched between it and the cage. Look at a freshly removed filter and you will see what I mean. The flat surface can (and often does) look like crap but it does not matter. What is VERY important is that when you install a clean filter you get your hands in there COMPLETELY around the entire filter and verify by feel that the cage is pushed inside the boot and captures the foam. Visual is not enough, sometimes it looks good and a little pressure up on the cage causes it to pop into the correct position where it was not before.

+1 on that statement! There is no way that you can tell if the filter is seated unless you feel it by hand.

And another +1 for good measure.

I seat it in the bottom lug first and then the other 2 clip in as well. Slap the retainer in and then use one hand to push the filter in towards the engine while you use the other to trace around the outer edge doing as described above.

I really like the way that the foam overlaps the sealing edge. I never use any grease on the surface either. When you remove it you'll be able to clearly see where it has sealed.