Fuel going stale?

[cheese]

So how long before my petrol in my container goes stale? I was talking to a guy today and he said only keep it for 30 days. True? What happens to stale fuel? does it drop in octane?

[kezzafish]

my mate has a magazine (i think it's the latest "dirt rider down under") it has a big article on fuel and storage etc, worth a read. From memory... it does drop in octane and they say don't store fuel for any period of time... i believe their phrase was " if it comes home with you... put it in the lawnmower" or something to that effect. But fuck that i say, i'm not paying 2 dollars a litre and biffing it out. It's a really good read tho. there's interesting info on race fuels and octane fluctuation from the pump etc

[barty5]

call round i have that mag ypu can have a read it a 2 part thing started the month before. But yes it dose loose octane. Ypu just need to ride more offten.lol

[JMemonic]

Been like that for years, and by international standards NZ must keep 3 months worth of fuel in stack, give the rate it drops in octane I wonder how this works.

[laRIKin]

So how long before my petrol in my container goes stale? I was talking to a guy today and he said only keep it for 30 days. True? What happens to stale fuel? does it drop in octane?

True, ever since they took out the lead out of the petrol and boosted the octane levels with aromatics and it would evaporate out of the fuel and drop the octane levels.

Put some petrol in a small bottle and shake it.
When you undo the lid it will hiss like a bottle of fizzy drink.
Keep doing it and it will go flat and have lost a lot of it's octane rating.

So it is best not to shake the container or have it bouncing around in the boot of a car or pour it from one container to another to often.
As it will drop a little in octane level each time.

[wickle]

So how long before my petrol in my container goes stale? I was talking to a guy today and he said only keep it for 30 days. True? What happens to stale fuel? does it drop in octane?

how much are you storing! as I belive insurance companys can try and use it as a out if you are storing above a certain amount

[warewolf]

Been like that for years, and by international standards NZ must keep 3 months worth of fuel in stack, give the rate it drops in octane I wonder how this works.

It works because it is stored correctly? And/or it is not stored with all the components mixed together? Pump petrol is a variable blend of up to several hundred components; race gas is a fairly fixed recipe to give consistent results.

I'm not sure about the losing the octane thing. What is being lost is the most volatile (easily evaporated) components, not all of them are the octane boosters (aromatics), but rather the stuff that helps cold starting. If these components burn more readily, losing them would potentially slow the burn and increase the octane rating. If using old fuel doesn't cause pinging, but does mean the engine runs like crap, then my thinking is probably correct.

Didn't we just have a thread about this? There's lots of good info on the web if you hunt for it - way more technical info than you'll ever need to know.

Two-stroke premix is another issue; that's not supposed to be kept beyond two weeks due to the oil reacting with the petrol.

Another reason not to keep petrol too long is that the recipe changes with the seasons.

[Reckless]

Cheese if you talking about your 2 stroke mix that has been on the shelf or in the tank for a month don't worry about it. Give it a shake and you won't even notice the difference and it won't do any harm. They are good old 2 strokes mate, run on anything!! If you don't want to use it, or loose it, chuck it in the car.
Now a 4 stroke is different, my mates WR450 wouldn't start one day after sitting for a few weeks and that was simply stale fuel. Drained it, got some new gas and it fired up right away after an hour of checking for spark etc. You've bloody near got to strip one of those things down just of get the plug out!!

In saying the above the other posts are correct it does loose octane but for our purposes its not a problem unless its been there for a year!!

[laRIKin]

I What is being lost is the most volatile (easily evaporated) components, not all of them are the octane boosters (aromatics),

Thank you thats the word (aromatics) I was looking for and have change my post.

[98tls]

Dont know about the fuel thing,i had an R32 GTR in the shed for 2 years with 1/2 a tank of Gas,once every 6 months it was started for a few minutes then left,it wasnt started once in the last 8 months of that period and when it was it fired up straight away and driven out of the garage,was nothing wrong with the gas.

[honda_power]

Cheese if you talking about your 2 stroke mix that has been on the shelf or in the tank for a month don't worry about it. Give it a shake and you won't even notice the difference and it won't do any harm. They are good old 2 strokes mate, run on anything!! If you don't want to use it, or loose it, chuck it in the car.
Now a 4 stroke is different, my mates WR450 wouldn't start one day after sitting for a few weeks and that was simply stale fuel. Drained it, got some new gas and it fired up right away after an hour of checking for spark etc. You've bloody near got to strip one of those things down just of get the plug out!!

In saying the above the other posts are correct it does loose octane but for our purposes its not a problem unless its been there for a year!!

my old crf250 has been out of action since the beginning of the year, fixed the shock and started her up on one year old fuel haha... so 2 weeks? nah. yamaha thing haha

[notch]

The volatile vapour components can travel through the plastic in plastic containers. Fuel stored in steel containers that are airtight lasts a lot longer.

[Buddy L]

my old crf250 has been out of action since the beginning of the year, fixed the shock and started her up on one year old fuel haha... so 2 weeks? nah. yamaha thing haha

Same i just start my bike on the weekend after about 8 weeks of not riding and she fired up after a couple of kicks.
I would always emty my gas cans of premix into my ute, after each ride as i didn't want premix sitting around for a while.
Ute would run alittle smokey but at lease everything was lubed up good.

[cheese]

I basically just keep topping up my fuel every so often adn don't really let it run out. So the fuel is never that fresh really. I think that I'll use up what I have and then get more. I went through about 2 full tanks at woodhill today. I had a silly crash and have a sore knee and a massive bruise on my leg that if it was just slightly more to the right I'd be worried about making any more kids!!!

[krad_nz]

Nice to meet you at wood hill today Cheese

Stupid fouled plug ruined my first hour of riding though!
Tried the convict and criminal tracks once SpikedPunch had enough and they were definitely challenging. Took a few detours but my excuse was that I was already pretty stuffed by this stage.