I have two twinairs. Both have the same appearance. Last night I looked at my 'spare'. It's oiled (!..note to Lutz! ;) ). Same thing.
A closer look at the 'hole' shows what I'd describe as a single layer (one cell thickness) of foam. You can see the structure of the cells in those spots. Doesn't seem like a decent filtration situation to me.
I didn't look at my filters when they were new...maybe they all look similar?
Mikeb: I'm not talking about something you're going to read a paper through or anything..just pinpricks of light.
I have a notoil in the bike at the moment. Haven't checked that.
Did ask twinair about it (boyesen bought 'em, I think). Haven't heard anything from them yet.
What are they going to say? 'Yep. Yours is broken. Buy a new one!'??
The filter I checked last night, I used a halogen shop light. I don't think you'll see much with a florescent or incandescent.
Maybe much ado about not much. Doesn't mean I like it any better.
Thanks for looking!