Supermarket Fuel

[JackButler]

I seem to be having a run of older bikes with poorly carburettors & talking to the owners the common thing between them seems to be supermarket fuel.

I don't know how to post piccys on here, but I have one stripped down & there is a visible green coating on the main jet, which I can only assume is 'god knows what' breaking down the brass.

What on earth are they putting in it these days???

[Bhud]

What's in it? That's a good question. I don't know.

I used to have problems with fuel even from proper petrol stations, but it wasn't gunking, just water/silt from, presumably, fuel that had been sitting in their forecourt tank. Nowadays I don't have any issues, but I only ever buy the more pricey option at the pump.

When you get an old project bike, there is usually lots of green gunk in the fuel system that you need to clean out. It's commonly called varnishing, and I've heard that it's a result not of petrol but of petrol stabilising (evaporation-limiting) additives. I'm not sure whether that's accurate, but it seems to make sense. In theory, and this is just what I have heard, you should not be getting varnishing at all with the addition of ethanol. Ethanol may cause other problems, dissolving rubber parts and binding with water, but it shouldn't cause additional green gunk varnishing because it evaporates.

The composition of modern petrol is of interest to everyone who runs carbs, and I'd like to learn more about it.

[JackButler]

[MarJay]

Ok so you may be one of the last people to know this, but all petrol is e5 now which is 5% ethanol. Ethanol is used because it's a biofuel so the process of manufacturing absorbs CO2 from the atmosphere. It's not just supermarket, it's all fuel now.

All pumps are marked e5 now. e5 does attack brass parts. You can remove ethanol from fuel using a simple process involving removing the fuel from the bike, adding water to it and allowing the fuel to settle so you can drain off the mixture of ethanol and water at the bottom of the fuel.

The EU and the UK government want to proliferate the availability of e10 which is 10% ethanol, which WILL completely fcuk old bikes. Hopefully it'll be like Super Unleaded where it is an option rather than the only choice.

I suspect you're getting water in your fuel, because most bikes aren't that bad unless they've been left with e5 fuel in them for years and years. Google how to check for water, and google how to remove the ethanol from the fuel.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[JackButler]

[Easy-X]

Ethanol is hygroscopic, i.e. it literally sucks water from fresh air.
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[MarJay]

[stinkwheel]

That green shit is corrosion. Brass is a copper/zinc alloy. It's very stable but it will corrode if exposed to air and moisture. Probably caused by the bike sitting unused for a protracted period with a little moisture in the float bowl. Usually accompanied by lots of white furry shit on the inside of the float bowl too. Ethanol wont be helping in terms of moisture sinking to the bottom over a longer period.

If you've got an older bike that isn't "ethanol safe" you can add a shot of stabiliser to the fuel when you fill up. I'm using one called ethomix in my '91 VFR750.

If it's going to be parked up for a while you should run stabilised fuel through it or drain the float bowls (either with the drain screw or by turning off the petrol just before you pull in and letting it run out before killing the engine). Brim the tank with stabilised fuel too to stop the inside rusting.
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“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.

[slowside]

I don't think it's a supermarket fuel problem. As others have posited, it's an E5 problem combined with lack of use.

I'm sure even Shell's finest, squeezed from the thighs of a virgin, drink it and gain virility and charisma V-Power would end up as a miserable green scum if left long enough.

[MarJay]

[stinkwheel]

[xX-Alex-Xx]

[Nobby the Bastard]

I've never had an issue with bike 25 years old and supermarket fuel but by the same token a tank of fuel will go through in a week so it never got a chance to absorb much water.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[MarJay]

[redeem ouzzer]

The only bike i don't have an issue with is my YR5, because it's on premix and the oil in the fuel seems to help stabilise it and stop corrosion.
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Be a REAL MAN!

[steve the grease]

You're lucky.I have a Cagiva 350 with a plastic fuel tank. The dissolved water in the fuel causes the plastic tank to swell up, to the extent that its impossible to refiit the tank if it is taken off. Ducati have had huge problems with this , and have been exchanging tanks for customers ( believe all they do is dry them out and send them out again). ( Google it) As a result I have to drain the tank if I'm leaving the bike standing for more few days. I don't know whether plastic tends to atttract more condensation and then water in the fuel than a steel tank , but E10 is going to make life even more difficult for owners of older bikes. Oh nearly forgot I also run the carb dry with the petrol turned off. no problems with rubbers yet.

[weasley]

[JackButler]

OK. So where's the best place to get Viton 'O' rings, 'cos I'm buggered if I can find all the right sizes from 1 supplier.

I've looked at : Eastern Seals - Seems to be the best

Simply Bearings - Some, but not all sizes

Bearing Boys - My goto place for such things.

Is there a magical one with online sizes/purchasing I've missed ???

[redeem ouzzer]

[MCN]

Supermarket fuel is normal fuel without the badges and some additives.

I put Badged fuel in my bike coz they can use the higher octane that many supermarkets don't sell a lot.

The car gets supermarket and it never misses a beat.

Old bike with mottled history and suspect prastic parts in the fuel system is the issue.
Overhaul the fuel system and upgrade.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[stevo as b4]

Anyone who's increased the compression ratio of their engine during tuning work, what do you like to use:

1, Shell/BP/Esso etc 98RON fuel.

2, The above but with an octane booster additive such as Millers CVL turbo, or Silkolene pro boost?

I ask the question as I'm back in the high compression club, and don't want to melt pistons on 95RON.

I've holed a piston using 95RON in a bike in the past so don't want to use it again.

[redeem ouzzer]

[UncleFester]

It's not that it absorbs water so much that is the issue ... more that a partly empty tank allows condensation to form which provides the source of the water FOR it to absorb.

Either drain it bone dry or keep it absolutely brimmed and use it. The exception for me is the mower / chainsaw / leafblower - they get turned upside down and drained dry before storage.

The lower the octane, the worse the problem is. Everything i own gets 99 / Superplus.
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Module 1 and 2 passed - October 2014. Happy owner of a 2017 Z1000SX, ex owner of a YBR125 / CB500 / VFR800.

[JackButler]

I've been doing a lot of research and this is a real hornets nest isn't it?

It seems to me that most standard unleaded 95 is already at 10% levels of ethanol, E10 is not just coming . . . It's already here.
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I clean my guns with the tears of the snivelling, left wing scum.

[Sister Sledge]

Reading through this had probably answered a question I was puzzling over. My 404 (a 2004 bike) uses a mix of plastics including a fuel tank.
The bike is stored indoors and isn't ridden during the colder months except to run it to temperature in the shed.
I turn the fuel off and nothing leaks (taps etc) and still I can get a whiff of petrol some days I go in there. I now suspect it's slowly leeching through the tank itself!
It's nothing bad but it is noticeable.
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CCM 404 DS