When I first got the bike, and start changing out items.
I never liked how the backfire screen didn't push hard into the airbox.
I changed that out to the no toil Super-Flo cage, that seemed to make a much better seal.
What I think I've done somehow
Is the last time I had the rear of the bike up (months and months ago)
I didn't seal the boot back onto the intake of the carb right.
In the past, I've had to undo the screw on the clamp, go in with needle nose pliers to pull on that little tab on the boot as I'm lifting the back end up to get it to pop off.
I undid the bolts of the sides and the top one, moved the rear up a little so I could put the side bolts back in there holes (do that with everything to keep track of them) went to undo the screw on the clamp, and saw the boot was off!!!!!!!
Clamp with done up.
What I think I have done, was when I had put it on, I didn't put it on all the way and I have done the clam up on the end lip, and not over/past it. and it's popped off, when the bike is sitting on the ground it "looks ok" but when riding I bet it will be opening and closing letting all that dust in
After Jim pointed out the pro seals the other week, I put them on all 3 of my CRF's lol
Not that I have an issue with mine or the wife's R's, but I want to keep it that way.