The hidden filter is in the fuel line right at the tee. I did it with the carbs still on the bike, its real tight in there. I used needle nose pliers with a 90 degree bent tip. Take spring clamp from end of fuel line, slide it up a ways, pull fuel line, filter will be down there in the end of that fitting right before the tee. I installed an in-line up near petcock, heard of some guys depending on petcock filter in tank and not installing any other filter.
