Tip for diagnosis problems with ethanol/water in fuel

[Robby]

This is for people who have a carbed bike and are paranoid or concerned about the ethanol mixing with water in the tank and dropping out of suspension in the fuel and leaving you stranded when you switch onto reserve.

Put a few drops of blue food colouring in the tank.

Food colouring will not mix with petrol. It will mix with an ethanol-water mix. So if there is a puddle of dilute ethanol in your tank, it will now be blue. If you're concerned about having this crap sitting in the bottom of your tank, run the bike on reserve for a minute.

If you have a fuel filter, you'll see that it now has blue in it. Alternatively, crack the drain screw on the lowest carb and see if blue stuff comes out.

For the truly paranoid, or for old bikes that spend a lot of time sitting, you can extract the ethanol using water. I mix a litre of water and food colouring with 10L of super unleaded in a plastic container, give it a shake, and leave it overnight. Next day I drain off the blue water and measure it. Super unleaded is up to 5% ethanol, so I can expect to have up to 1.5L of blue water (1L water + 500ml ethanol) to remove. In practice it's more like 300ml ethanol. Now I have ethanol-free petrol which is still high enough octane to work, my old bike only needs 91 RON and the stuff I'm left with should be around 94.

[stinkwheel]

Although the dye is probably unecessary, you can usually see water droplets sat in the bottom with a torch or if you drain some fuel from the float bowl into a jam jar.

Some bikes used to have a sediment bowl on the fuel tap, you just unscrewed it to see if it had trapped any water or bits of muck.

Perversely, one of the fixes for water in your fuel is to add some ethanol and shake it up.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Robby]

The dye helps for seeing it in a transparent filter, or in low light.

[sickpup]

[stinkwheel]

[sickpup]

[stinkwheel]