It's not controversial,  it is based on opinions.  Some will give their opinions and whatever thought they have to back it up, others will disagree with the same and offer other opinions and the thoughts to back it up.

I never really considered very much where the brown stuff came from, but then it occurred to me that gasoline is just part of the spectrum of stuff that gets cracked out of crude oil.  Some of the other things that get sorted out in the distillation tower is solid waxes, heavy oils and such.  These are the heavier elements.  Gasoline isn't the lightest of the lot either, benzines and naptha spirits are a good bit lighter than gasoline.  Gasoline is a mixture of the middle volatile elements.

So, why should our gasoline,  which is a middle product, not contain some of the heavier elements dissolved in it?  Some heavy waxes and oils, dissolved in suspension?

And why under conditions of temperature change, evaporation, oxidation and idle storage, shouldn't some of those heavy elements perhaps come out of suspension?

We all know about the varnish that shows up on carburetor parts, we all have sprayed it away with carb cleaner many times during our mispent youths.

Is varnish a product of heavy oils and waxes coming out of suspension as the carrier (gasoline) evaporates?   Think of salt coming out of salt water and think of your hair and your skin after swimming in the ocean and drying off.

I think we need fuel filters, as some of the air jets and fuel jets in our carbs are smaller than the 1/16" main jet mentioned up thread and can be affected by particles of waxy varnishy trash brown trash stuff.  

Sorry Greg, it's an opinion.   I have seen petc0ck screens blocked so badly with varnish that fuel flow was affected on reserve.  Now did my bike's previous owner let most of a tank of gas evaporate to make this condition possible, yeah -- I think its real likely.

Would Seafoam or Stabil gasoline conditioner help?   Heck yes, why do you think they work so well people swear by them for winter storage.  They keep the brown crap from coming out of suspension during cold idle storage.  

Surprise, if you are already poluted with varnish these same stabilizers and cleaners can also peel pieces of it off the inside of the walls of the gas tank and let them float around freely in your fuel supply too.

So, it's an opinion.  Your mileage may vary.

Other biker groups have considered this topic and have similar but slightly different opinions.

http://www.wetleather.com/node/218


Farmers deal with this storeage issue more than bikers do since their stuff sits a lot.   This is what they have to say.

http://www.thefarm.org/charities/i4at/surv/sta-bil.htm


Also, consider that every gas pump has a fine paper filter element that gets replaced regularly.  This brown residue in the gas isn't a new issue to the fuel industry.

http://www.nationalservicestationsupply.com/index.asp?PageAction=VIEWCATS&Cat...


So, I got me an opinion -- don't you?


<grin>


Oldfeller