bolt on cone filters suck in water when it rains,mud when off road fella even 500cc gp bikes had air boxes,kinda says it all. i thought twin air did an after market filter though,worth a google
Also seen a sock type cover called Outerwears for the foam/mesh type filters, bit like Gortex I reckon, lets air through but not water,popular in the states.
If you're going offroad defo keep the standard airbox, filter and snorkel. Also make sure the airbox sidepanel is sealed properly and oil the filter. I had all sorts of aggro with mine while greenlaning then found out the foam filter was fecked, the side panel was leaking and the airbox had loads of water/ crap in it. Had to strip the lot down (and the carb) and clean it all out with carb cleaner. Runs fine now though.
even 500cc gp bikes had air boxes,kinda says it all. i thought twin air did an after market filter though,worth a google
