Don't ever think of separating the carbs and avoid 'extra' inline fuel filters. A good petcockfilter is all what it takes and if it's not there, restore it. I've seen enough misery with these extra filters. Some are lucky, but many experience intermittent problems and it's exactly that 'intermittent' occurence of problems that can drive you insane. Such a filter may work for weeks and then all of a sudden it causes problems but because it has worked flawlessly for weeks you will not expect that filter to be the cause. It helps when fuel lines are cut to the original length. Sometimes (not always) the Parts List gives a clue. For a CB 550K, K1, K2 standard length for the two fuel lines is 18 and 30 cm (old style fuel cock) or 17 and 28 (new style fuel cock). Ideal diameter is 5,5 mm. Again, avoid the use of inline fuel filters.