Unfortuneately i do not have another air cleaner to try, but when I get home from work I will try turning the spike so it is pointing up to see if theat helps
I had the same problem that I found the answer to here on BigDogBiker. I turned my spike air cleaner from facing forward to pointing straight up. Doesn't Carb fart anymore just like I had and you described.
I believe the PRE-FILTER being refered to is also called a rain sock which slows down the air from being forced in there. Put the prefilter on and try it... if still doing it go up on int jet!
