Help! Can't get YZ running well after day in sand

[NYCBanshee7]

I just picked up a 2005 YZ 125 w/ FMF pipe, v-force 3s and what looks like to be the stock foam filter. I took it out for a day last week in a sandy spot in NJ. I was following alot of banshees and it was very dusty. Today, I took it out by myself and it ran horrible. But it doesn't look like any sand got through the filter. I was just wondering what you guys run in your dirtbikes in sandy areas. Should I get a K & N w/ and outerwear?? Any suggestions would be appreciated.

 

Thanks for your help