Join Date: Dec 2012
Location: Canada / Thailand
Mentioned: 0 Post(s)
Sand is composed of very fine particles, so the tire is pushing it out to the side as well when you ride thru it. Also, the air behind the fairing is in a negative pressure zone - air pressure is lower there. This creates a partial vacuum and the sand - being light - rushes into this area.
Water and mud, being much more dense, will not travel so far and need to be 'thrown' by the tire to hit the bike.
Make sure you have a good seal around the air cleaner and the airbox, sand gets everywhere.