You guys have got it right. An over oiled air filter will make it seem like the choke is on and mess with jetting.
No do not use motor oil it is way too thin and not even close to being tacky enough.

I change my air filter every ride. I put 100+ hours on the same top end with no decline of power. I thought it would be time to change it any way. I took it to the Honda shop to get the cylinder honed and they said i was just wasting my time changing the top end. It didn't need to be changed.

99cr250, Thats the point. It is very important to not only service your air filter frquently but properly. It makes your bike and $$$$ go a long way.

Get this,
I'm cleaning a filter I’ve have about 4 weeks now, it's a Yamaha filter, and the glue breaks down and the panels come apart. I cleaned it as I cleaned my other filter, which lasted a year. Liquid detergent and warm water. I'm pissed, going to take it back to Yamaha and use a twin air again. Anybody else run into this?

Dave

I hear that if you switch from No Toil to petroleum or the other way that the glue will come apart.
Also if you over oil the filter the oil will line the inside of the air boot resulting in a slightly sticky finish. This is of no consequence but can be used to indicate if dirt is getting by because it will catch on the boot wall.
Also a good clean air filter can result in a long life for a 2 stroke. 2 stroke engines are used in some very light airplanes and they are getting something like 1000 hours or better on a top end.

Is it ok to use K&N airfilterl oil spray on a dirtbike filter, I have it for my street bikes.

Some thoughts on filters, during the moto-x season we change the filter after every race and practice, thats 4 times per day, we have never experienced any abnormal wear patterns. We apply oil by submerging the filter after cleaning and then squeezing out the excess and leaving to dry for at least 2 days, clean filters are then stored in zip bags to maintain the tackiness.
We figure oil is cheaper than pistons!