Question about my air box and The K&N filter

[bandit390]

I notice on the bottom of the air box about 1 inch away from the front there is a penny size whole. Now does the 400ex air box come stock like that? or maybe the owner before me put it there.

Also when I took my lid off I noticed some sand in there, and been told that the K&N filter lets more threw the filter. Should I not add the filter or will it not let the sand by?

[BornOnFire]

The hole is normal and is most likely the airbox drain with the plug missing. A new Model comes with a piece of clear tubing attached with a plug in the end. That way you can see if any water got into the box. As far as the K&N Filter goes, you did ok there. Put that bad boy in. If you are riding in a lot of areas where you may encounter an above normal amount of dust, sand, or things of that matter, you can buy an Outerwares filter cover. It is essentially a big sock that fits over the K&N and prevents the "Big Stuff" from getting there. The sand you saw probably came in through the drain hole.

[JabberJaw]

Originally posted by bandit390
I notice on the bottom of the air box about 1 inch away from the front there is a penny size whole. Now does the 400ex air box come stock like that? or maybe the owner before me put it there.

Also when I took my lid off I noticed some sand in there, and been told that the K&N filter lets more threw the filter. Should I not add the filter or will it not let the sand by?

The hole you are refering to is a way for water to drain, should it get inside your air box. There should be a plug on the outside of the air box, if it is missing, you can get a new one for cheap.

As far as the K&N filter, as long as you put the pre-filter on it, you will be fine. The pre-filter is like a sock, or cloth covering for the filter itself.