OK after I performed my last service I started her up and while leaning over the air box I noticed what seemed to be puffing from the seal area of the lid and box. I removed it and the seal was perished and had a section missing so off I went to Clark rubber and made a new gasket. I had already replaced it when I realised I should have confirmed it was puffing out and not just sucking and sucking less if that makes sense. The only way I could see it being positive pressure at the air cleaner was from the crank case but how much is there at idle? There was no sign of oil residue on the filter side of the tee in and I have no catch can installed yet. Any ideas fellas?