jamesgs4,
Well, the allowable sediment in gasoline dispensed at the pump is .05% If you fill up with 2.5 gallons then you could have as much as .05% X 2.5 = .00125 Gal or .16 Oz. of sediment per fillup. Over the course of a year, filling up every week with 2.5 gallons, that accumulates to .16 Oz X 52 = 8.32 Oz of sediment .
Here is a glass with 8.32 Oz. of rice in it. That's how much crud could potentially go through your tank every year.
So, that's the crud I was referring to. Even if you start the year with a clean tank, about 4 Oz of sediment will have passed through the tank in 6 months and a lot of that is sitting on the bottom of the tank and gets picked up when you go to reserve. Much of the sediment is small enough to pass through whatever filter you have in the tank and in line so it ends up in the bowl of the carbs, so I try to remember to drain the carb bowls every once in a while as well.
So, I try to remember to drain the tank once a year by selecting the prime position on the petcock and run the gas through a coffee filter to a gas can. And, I never use the reserve position on the pet cock.
Cars, of course, have the same problem, but they do not have a reserve function that draws gas from the bottom of the tank and the fuel pump is inside the tank positioned about 1 inch above the bottom. They also have very large fuel filters compared to a motorcycle. The fuel pump also allows cars to use a very fine filter because the pump pushes the fuel through the filter. We don't have a fuel pump, so if we use a very fine paper type filter, it soon clogs up from the sediment because the fuel pressure drops as the tank empties. The best fuel filter for motorcycles is not a filter at all, but an old fashioned sediment bowl as found on my Honda CB450 and CB750K-4 petcocks. I can remove the sediment bowl and see any collected sediment and just dump it out. The sediment bowl system does not offer any restriction to fuel flow either.
If you really want to get serious about fuel filtering, then you can get a vacuum operated fuel pump for motorcycles from JC Whitney and install a car type filter.
Sediment in the gasoline dispensed at the pump also creates a dilemma as to which gas station to go to:
1. Go to a new station because the tanks are new . OK. But there were probably a few shovelfuls of dirt thrown in the tanks during installation.
2. Go to a station with high volume of sales because the gas is always "fresh". OK. But those stations get more deliveries of gas every week. Dumping 2,000 gal of gas in the underground tanks stirs up the bottom sediment.
3. Go to a station with a low volume of sales to avoid #2. OK. But those stations might have "stale" gasoline or gasoline from the previous seasons blend.
4. Go to an older station to avoid #1. OK. But those stations may have rusty or corroded tanks and are producing there own sediment in addition to what comes in with the tankers.
So, go to a station that is 5 years old that does a moderate volume of business and avoid the days when the tanker truck comes. Use 89 Octane because there is a larger volume of that sold so the gas will be "fresher" and not likely to be from last seasons blend.
