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Itchytoe

2018
CB650F
Dec 15, 2019
Gasoline isn't a single substance, like water. It's a mixture of quite a few different compounds. That's why you can have different octane ratings. Butane, for example, is cheap and burns well, so it's a very common component in gasoline. Unfortunately, it's got a really high vapor pressure. It escapes the mixture easily and over time will completely vaporize out of your gasoline. That leaves you with only harder to vaporize and burn components. Eventually, the fuel becomes too difficult for your engine to vaporize and burn. How long that takes depends on the exact mixture and the conditions the fuel is kept in. Winter fuel goes through this process faster, largely due to higher butane percentages. Lower temps help slow vaporization rates. A couple of months probably isn't long enough to have issues with the fuel, but I've said probably before. If you add a fuel stabilizer, the odds of having any issues over a 3 month period drop to almost 0. Heck, you could probably extend that to 6 months and still be perfectly fine.

Ethanol itself won't be an issue a modern motorcycle. It can be a problem for old bikes with different gaskets and hoses, but modern ones were built with ethanol safe components. It isn't a problem. Water, however, is an issue. And ethanol loves water! They are like peas in a pod. Where can you find water? Well there's lots of moisture in the atmosphere. Some of it gets absorbed into the ethanol in gasoline. Over time, it adds up in your tank. Why is water in your fuel bad? Well it helps rusts metallic components, and doesn't burn very well. Two things you don't want your fuel to be like. I suspect a fuel stabilizer can slow this process as well, but I don't know for sure.

Like others have said, a fuel stabilizer and battery tender will see you through the winter. Just make sure it's only one winter. It won't keep you good forever.
 

Patent

2020
CB650R ABS
May 19, 2020
Riding Since
2020
My optimate 3 arrived today, It's fitted with a two-prong European plug. I'm not sure if that's normal here or if I got one from the wrong pile?

I can't be bothered enquiring about it or returning it so I've bought an adaptor which should arrive tomorrow, then I can plumb it in.

I did some research last night and based upon two reviews on Bennet's I think I am going to go with XCP Rust Blocker over ACF50, I'll do a post on it once it arrives
 

Brammers

2014
CBR650F ABS
Staff
May 30, 2014
Hampshire, England
All this talk of ethanol and water... Got me thinking...

Ethanol gets water from atmosphere, fine. Water is heavier than petrol. Water sinks to bottom of tank.

As there's no air down there and thus no oxygen, how does the metal rust?
 

Itchytoe

2018
CB650F
Dec 15, 2019
All this talk of ethanol and water... Got me thinking...

Ethanol gets water from atmosphere, fine. Water is heavier than petrol. Water sinks to bottom of tank.

As there's no air down there and thus no oxygen, how does the metal rust?
Oxygen can and does dissolve into the gasoline. It goes straight from the air into the gasoline. It's not enough oxygen to support combustion, but it is enough to form rust (and other oxides). From there, it can move through the entire mixture of gasoline, ethanol, and water. The water doesn't really sink to the bottom of the tank like you'd think. It tends to stay suspended due to the ethanol. Then you've got a tank full of gasoline, water, and oxygen. The water and oxygen simply does what water and oxygen does at that point.
 

Itchytoe

2018
CB650F
Dec 15, 2019
LOL, I'm an inspector in oil refineries and chemical plants all over North America. That's not exactly my area of expertise, but it's close enough for me to actually be able to speak somewhat knowledgeably.
 

Dankotaru

2019
CBR650R ABS
Jul 5, 2019
7000' ASL, USA
Oxygen can and does dissolve into the gasoline. It goes straight from the air into the gasoline. It's not enough oxygen to support combustion, but it is enough to form rust (and other oxides). From there, it can move through the entire mixture of gasoline, ethanol, and water. The water doesn't really sink to the bottom of the tank like you'd think. It tends to stay suspended due to the ethanol. Then you've got a tank full of gasoline, water, and oxygen. The water and oxygen simply does what water and oxygen does at that point.
This is a good post, and is really the issue that most fuel 'stabilizers' and antioxidant additives in fuel and lubricants are designed to inhibit- the effects of oxygenation. The added oxygen combines with a variety of both fuel and lubricant compounds to produce different carboxylic acids. While these acids can lead to well-known issues of varnish and sludge, they can also be highly reactive with different metals and are a prime source of corrosion, depending on the metal and acid type. You mentioned butane, for example, and it converts to butyric acid, which is highly corrosive to carbon steel. Hexane, also common in fuel, forms hexanoic acid, etc...

As an fyi that some might find interesting, and maybe you've seen it already given your line of work I @Itchytoe, there was a study done not too long ago on the effects of different fuel stabilizers, and most increased the water content of the fuel over a year (or six months, I can't remember) of storage. This was expected, since most antioxidants work to prevent oxygenation, allowing water to stay suspended and relatively un-reactive compared to the acids that would otherwise be formed. The study focused on how much engine performance is impacted by the increase of water in the fuel. Problems occured after about 20 oz of water was present in one gallon of unleaded fuel. The average amount of water in the fuel after the storage term was 3 - 5 oz.

Also, some of these additives don't just stay in the fuel. baugustine @baugustine had an image of light corrosion on the filler inlet of his tank, and someone said fuel stabilzer would have helped. This can seem improbable, since the stored fuel doesn't sit that high in the tank. But gasoline is full of different aromatic compounds, and there are additives that when mixed with these compounds will also react with both the air (O or N) and the metals to work as corrosion inhibitors. These inhibitors work to prevent corrosion inside the tank, not just in the liquid fuel. Salpn, for example, is a very common additive and will catalyze with chromium, iron, and nickel to prevent oxidation, so it works well with a wide variety of steels.
 

miweber929

2014
CBR650F
650 Alumnus
Staff
Feb 13, 2015
Woodbury, MN
Riding Since
1975
Yet so many people here seem to like Seafoam. 🤔
Use whatever makes you feel best.

While I appreciate F9 I don’t live and die by things he (or anyone else, really) says, especially since I’ve personally used SeaFoam for somewhere around 15 years now and have had zero issues with it. I can’t say the same thing about Stabil, which is what I used the 30 years prior and while it always stabilized the fuel, that tank of gas ran funny until it was gone and carb bowls would have a reddish varnish at the bottom and Pilot jets still gummed up after a few years.

YMMV, really you can’t go wrong with any good quality stabilizer.
 

baugustine

2014
CBR650F
Staff
May 21, 2016
Ventura, CA
It's probably also a safe bet that the formulations of the stabiizers have changed over the years. The gasoline certainly has, with seasonal blends, additives and ethanol.
 

JRinKtown

2018
CB650F
Jun 30, 2019
MY take: Stick to ethanol-free gas and disregard advice to use stabilizers. Keep tank full to avoid condensation, keep battery healthy (I like the Optimate 3 tender). Either ride it somewhat regularly for enough time to get the engine to full temp for a while so as to vaporize any moisture out or do not ride or start it at all during the winter. Starting it now and then or a brief ride of 10 minutes or so is worse than not riding at all, as it introduces moisture and doesn't heat it enough to eliminate it. That causes hydrocarbons and such to form in the oil. Here is a good testing video on the stabilizers:

Oh, and if you ride it, have a jerry can (plastic type) of ethanol-free gas to top up with after each ride. If you top up at a station, the hose contain 1/3 gallon of the gas used by the previous customer, and that's likely to contain ethanol.
 
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