With the potential purchase of a classic bike on the horizon, I started to look into various issues and one the keeps being raised is the amount of ethanol in modern fuel.
Do you E free riders… where do you get yours? I found a couple of potentially helpful sites.
Isn’t it mainly a problem with fibreglass tanks? The ethanol can eat away at them.
I don’t think it’s a major problem for the engine, especially if you stick to E5.
Good question. I too have been thinking about this. When did bikes start to run unleaded fuel? Will it damage a 1976 Honda?
Presumably a 1976 Honda has already seen a fair few litres of unleaded fuel through its carburettors…
My 1979 Guzzi with its Dellorto carbs seems happy enough on E5. I also put E5 in my Street Twin most of the time, although it runs OK on E10 if necessary. There’s no ethanol-free available in this area.
I was thinking of bikes that don’t get used much… becoming a bit watery and rusting the tank
My 78 Suzuki runs fine on E5 but I always drain the carbs when I put it away.
Preventing varnish effects I guess?
I’ve looked into this a bit in the past, it depends where you live but some of the pump “super” fuels although marked as E5 can be ethanol free (just legal arse covering). Sadly not the case in Cornwall.
If you check out Shell or Esso web sites you’ll find whether your in a potential ethanol free area.
I just know how long it takes to, get em off, clean them, reinstall. So much easier to drain and forget.
I’m late, sorry, been playing on the dark side. Ahem. 
E5 etc hasn’t caused any problems on any of my bikes. It causes a leaner run but my bikes always seem to run rich (cooler) so no problems. The Amal carbs have vapourised in the hot weather rather than any problems with the ethanol.
I was talking to the owner of this rather luvly piece of kit only yesterday about ethanol and the super looking fibreglass trackmaster tank. (I will get one of these as waiting for an alluminium one to be made is properly getting on my wick).
He obviously lines his glass/plastic tanks and hasn’t has any problems. I had a good feel around under the petrol cap - there was fuel in the tank - but everywhere was solid and glass smooth with the liner.
He also removes the ethanol with some bikes, I’ve never bothered, but it’s fairly easy to do if you are worried about rubber seals, hoses, carb parts etc melting away.
It always a good idea to drain tanks and carb bowls if the bike is going to sit for a while. Particularly over winter. Pilot jets blocked with varnish are a pain to clear if the carbs have to come off to dismantle and clean.
Here’s that flat tracker again as it’s so nice it’s worth seeing from the other side. Note how it’s been kept in racing format - brakes and gear change on the same side. I so want this bike, surely you can all club together to get it for me…over 
Sorry, a reread and saw I never said how to remove the ethanol. It’s pretty simple.
Ethanol attracts/sticks to water chemically (I forget what it’s called but it’s something scientific). So, instead of waiting for the ethanol to attract the condensation caused by the cold inside your petrol tank add additional water to the fuel before putting it in your tank.
Fill a suitable see through container with about 10% of the volume of fuel you’re going to fill it with with water. For interest mark the level of the water on the container.
Pour in your ethanol fuel. Give it all a jolly good shake to mix in the water. Leave overnight.
The fuel will separate and float above the water (this is why petrol tanks will supposedly rust from the bottom up with ethanol fuel - I’ve never seen this).
You’ll notice that the water level has increased as the water has now stuck to/attracted the ethanol. You can measure the difference in level to work out what actual % ethanol was contained in the fuel.
Syphon off the fuel and ta da, ethanol free petrol.
For the last dregs you can use a separating filter/funnel (easily available on amazonian for a few squids) that allow the fuel through but keep the water back. They actually do work very well as i have one on the shelf that I use now and again.
Be aware, however, that the ethanol actually helped with the power delivery, another scientific thing you can search for on Mr Google.
To be honest, I can’t be bothered doing all of that as I’ve not had any problems with E5 petrol. If I was really concerned with racing/antique/really expensive machinery etc I’d be buying in the ethanol free stuff but have you seen the price? Jeez, it’ll make your hat fly off 
I’ll just add a brief word to that and say that, if you’re going to use the method outlined above (the word is ‘hygroscopic’ Iron ;-)), then it’s accepted wisdom to use an octane booster additive to the now ethanol-free fuel you’ve created.
STP and Redex both do octane booster additives.
Rusting requires oxygen too. The only oxygen in the water at bottom of tank would be what gets dissolved in it from when it was at the surface, which I’d guess wouldn’t be a lot. Unless you’re in the habit of giving the tank a good shake to mix things up 
Changed my mind 
I was gonna try to read it but was scared by my potential stupidity of not understanding it!
You were right about the serial calamities though!
Steel corrodes in water through an electrochemical process that involves the reaction of iron in the steel with oxygen in the water (H2O).
I thought that was what I said, or are you saying that it only needs the oxygen from the water molecules?
I was relying on decades old knowledge I dragged up from my brain so I just did a Google search to see if I could find a more reliable source than that. I don’t know if you count the BBC’s GCSE revision resource on rusting as reliable, but that says you need oxygen from the air too. I’m willing to beleive that the real answer is more complicated 
