I'm going to jump in here, knowing full well that I am WAY out of my league, but being that I was the first poor bastard to respond to the original post....
I think if we all step back here a second, we can all recognize that the irony here lies in the fact that the OP stated clearly, that in fact he didn't know if an in-line filter should be used, in addition to the stock filter in the tank. Keep in mind, he finished his post with the fact that he couldn't get his bike to run WITH an in-line filter in place.
So the answer to HIS question is, no, you definitley do not NEED to have it (and in his case, you probably should not, if in fact you want to ride the bike, as opposed to stare at it in frustration).
I may have opened a can of worms with mentioning that I do indeed use a filter in my fuel chain - and the reason, shockingly (...wait for it), is that the PO of my particular bike, was neglectful. He had them on there, undoubtedly, because like all the rest of his "fixes," it was easier to do that than fix the tank.
I put a new set on there because I admitted to myself that I was not going to fix the tank first. Something I have come to learn was a mistake. I now realize I should have started at the source of the juice that runs this thing - and instead moved along to other fixes, that were all, very probably, somehow effected by this poor decision. But that's just me. I made the call, I live with the results.
This thread has become a sort of pissing match, which begs the question, what are we all trying to achieve here. I think TwoTired correctly stated that there is no real need for the in-line filter, if the bike is to be run the way Mr. Honda intended. In fact, there may even be some drawbacks to the practice, that we can't actually see (small particles).
For those that have "successfully" used in-line filters, I think we need to admit that this has been done with a certain amount of "faith" (not religion, mind you), as TT pointed out, in that there is no data to substantiate our "feeling" better, at having these things in line.
That being said, many have been able to enjoy their rides with these buggers installed, and maybe even more so, because they feel they won't be stranded on the side of the road, because of particles clogging the carbs. I think that has a value too. It might not be the best way to run the bike, it might not even help. But peace of mind is priceless, especially on a motorcycle.
I am likening this debate more and more to the loud muffler preference. It's not quantifiable. So many believe that the loudness makes them safe, but without interviewing the 100's of drivers they rode near in a given day, how would we know if it prevented an accident. They may have been surrounded by generally attentive people that day. Or the next day, loud pipes and all, they may find themselves surrounded by folks who wouldn't pay attention to a shiny new Fire Truck with it's lights/sirens on (I've seen this accident scenario more than once!), and get in an accident anyway.
With no conclusive data on in-line filters, we have delved into the realm of superstition. And honestly, I am pretty superstitious. If we avoid stepping on the cracks, thereby taking us a little longer to get to our destination, we haven't drastically upset our lives, but we may be late to an appointment. But who knows, we may in fact have avoided getting hit by the bus that was out of control just seconds before we got to the curb.....
