Getting Rid Of Rust in Gas Tanks.
Some of you with older Iron may notice that your tank/s have rust inside. Then you also notice that your fuel filter seems to be getting clogged a bit more as your ride ages. You do check your fuel filters do you not? Minute particles of rust can and will, over time, ruin a carburetor if left unattended. Being that there are so many small holes inside the carburetor it only takes minuscule amount to give you hard starting, bad idle or worse, a dead engine in the middle of nowhere. On a fuel injected engine the rust can wreak havoc in the injectors as well causing a sporadic spray in the nozzle. (ask an older guy what that means ladies next time he takes a leak. Then you'll know why the toilet lid is wet. lol) Its akin to a water hose when you hold your thumb over the flow of water and the spray is harder to control.
Anyways, if you don't like messing with harsh chemicals an environmentally way to get the rust out of a tank, (Tank/s removed from the motorcycle of course) is with good old BB's. Pour in some BB's, put the cap on and put the tank on a paint shaker. Now I know that not many of you have a paint shaker handy but a small paint store will sometimes do it for you during an off hour. Your best bet is to wrap the tank in a heavy t-shirt or some foam to keep the noise down. After that's done, pour out the BB's and blow out the tank/s with air before using a tank sealer you can buy at automotive shops, bike shops or marine shops. Don't forget to replace your fuel filter before gassing her back up again.
Here's another fuel tip: Sometimes water gets in your fuel by either a bad sealing cap or even from some gas stations underground tanks. If your engine was running fine before you fueled up and shortly after begin running erratic it may be from water in the fuel. Water can also accumulate in your fuel tank from a motorcycle that has been sitting a few days with half a tank or less of gas. Humidity can also play a roll on just how much water condensates inside you gas tank/s. A good rule of thumb (thumbs a little guy you know) is to completely drain your tank/s at least once a year. More if the humidity in high in your area. To do this, run your bike down until you have to put it on reserve then make sure the fuel shut off (petcock) is turned off. Grab a clean gas, remove the fuel line from the shut off (petcock) attach a short piece of new fuel line to the petcock and the other end in the gas can. Turn on the fuel valve and let what is left in your tank/s drain into the gas can. Pour that gas into your cars fuel tank instead of on the ground. The small amount , even if it has water in it, is so mute when it mixes with twenty gallons in your car and it will burn out.
Water is heavier than gas and will settle in the bottom of you motorcycle gas tank right at the fuel valve. That means that your float bowl gets a heavy dose of water instead of gas causing the engine to not start or be hard to start until the water has been expelled.
When I used to fly in small planes with a couple of friends we always checked the fuel for water before we took off. Under the wing is a little valve for a special bottle to fit into. We'd take that little bottle and push it into the hole to drain out a few ounces of fuel. Then when we held the bottle up we could see if any water was in the bottom of the bottle. (Mix some oil and vinegar together and you can see what I mean). I often wondered just how many bike shops simply drained the gas tanks and carburetor bowls after checking for water in the fuel and charged a hefty repair bill for something so simple.
You can buy a medium sized syringe at the drug store to syphon off fuel from your from your tank with a small fuel hose attached to the end where the needle was. Insert the hose into the tank all the way to the bottom and pull the syringe plunger to fill up the syringe half way. Pull it out and look for beads of water in the fuel.
It all sounds so complicated but its not really after you have done it once.