Stale fuel? Explain

[Metal Doctor]

So whats the deal with stale fuel???

heard this so much "could be stale fuel mate"

At what point does fuel become "stale". i know if you leave it in your carbs for too long without running the bike it turns to goo, but how old does it have to be before it affects the performance of the engine??

[bogan]

Depends on the volume, if you have a full tank, it'll last for months with no change (I do this with pre-mix for my dirtbike and 3 months is good). Only a few liters in the tank and a month or two could see it turn to shit. The carb fuel goes off quicker, but you get fresh stuff through quickly so no bother, and it'll take ages to turn to varnish.

I'm sure there is some chemical explanation, but the practical one is enough for me.

I've never had stale fuel in a 4T, but my 4Ts are generally used weekly, had it on my 2T dirtbike, felt like it was 'hunting' for the powerband but couldn't quite find it.

[Akzle]

the evaporative stuff evaporates, leaving the less-volatile shit. (goo, or, after a few years, hard resin)

[FROSTY]

Our petrol in unzud is such rubbish it needs octane boosters to get it to work. over time the boosters "flash off" leaving very low octane fuel that bikes don't seem to like much

[Metal Doctor]

thanks for the explanations!

a couple of people told me that NZ fuel was a bit shitty, never had any problems my self, but my dad could smell that it wasnt great fuel!

[schrodingers cat]

Get a glass jug and put a litre in. Sit and watch it for a bit.
Look at all the wafty goodies wafting away.
Bye Bye exciting wafty bits. Hello stale remaining bits, I guess its just you and me now the excitment has left

[Ocean1]

thanks for the explanations!

a couple of people told me that NZ fuel was a bit shitty, never had any problems my self, but my dad could smell that it wasnt great fuel!

There's three types of fuel in NZ. Stuff out of Marsden point, made to recognised international standards, Imported stuff, made to recognised international standards, and blends of the above two.

By far the most likely to be causing any trouble is the imported stuff. For a while we got quite a bit of Russian stuff, it definitely smelled different, and usually arrived with an unusually high water content.

And the difference between brands in NZ? It all arrives down the same pipeline. Any difference can only be in the additives, usually well less than 0.01%, and usually arriving in the same container, from the same supplier. You work it out.

And yes, the evaporatig thing is correct, petrol isn't a single chemical, it's a range of chemicals split from an even wider range: crude oil. The more volitile elements evaporate more quickly, leaving a range of chemicals some motors might struggle with. How long tha takes depeds on temperature and how much air circulation there is within the tank. That's why modern cars have sealed tank caps with small pressure/vacuum break valves built in.

[caspernz]

There's three types of fuel in NZ. Stuff out of Marsden point, made to recognised international standards, Imported stuff, made to recognised international standards, and blends of the above two.

By far the most likely to be causing any trouble is the imported stuff. For a while we got quite a bit of Russian stuff, it definitely smelled different, and usually arrived with an unusually high water content.

And the difference between brands in NZ? It all arrives down the same pipeline. Any difference can only be in the additives, usually well less than 0.01%, and usually arriving in the same container, from the same supplier. You work it out.

And yes, the evaporatig thing is correct, petrol isn't a single chemical, it's a range of chemicals split from an even wider range: crude oil. The more volitile elements evaporate more quickly, leaving a range of chemicals some motors might struggle with. How long tha takes depeds on temperature and how much air circulation there is within the tank. That's why modern cars have sealed tank caps with small pressure/vacuum break valves built in.

C'mon now, don't be giving away too much of the insider info...:shit:

How long before someone asks how to check the opening pressure on the PVV, that's if they can locate it...

[Metal Doctor]

Ok heres a one for all you knowledgeable folk!

is high octaine racing fuel normal fuel with shit loads of booster in it, or, is it a more refined cleaner fuel?

Thinking of getting some.

[Brett]

Definitely goes stale....my lawn mower proved this. I was mowing are rather large lawns and ran out of fuel. We live a little bit away from the nearest fuel station and I had some old (like 2 year old) fuel sitting in the back of the garage which I thought I would give a go. Well, it ran for about 5 or 10 minutes and then suddenly died. When I pulled the starter, the blade spun freely - ie no motor compression. Pulled the head off and sure enough, one of the valves was stuck open! (rather tightly too!). Got piston free, oiled it up a bit, chucked in fresh fuel and away she went.

[Ruahine]

Ok heres a one for all you knowledgeable folk!

is high octaine racing fuel normal fuel with shit loads of booster in it, or, is it a more refined cleaner fuel?

Thinking of getting some.

Do you mean trying 98/95 over 91? I wouldn't bother unless your bike is designed for 95. Octane rating relates to the fuel's ability to self-ingnite under compression. Higher octane being more resistant. I don't think the higher octane is any "cleaner" or "refined".

[Ocean1]

Ok heres a one for all you knowledgeable folk!

is high octaine racing fuel normal fuel with shit loads of booster in it, or, is it a more refined cleaner fuel?

Thinking of getting some.

Octane booster? It's simply one of the chemicals that usually make up petrol anyway, they just add more of it. Octane ratings are largely bullshit anyway, a calculated performance value, rather than any level of "goodness". Even ACTUAL Octane rates are simply indicitive of another more accurate performance value, knock rate, which is the actual range of conditions that the fuel will detonate at.

Racing fuel has a slightly higher knock rate, and because of the additive used to make it that way it's not strictly speeking "lead free".

And unless your engine is specifically designed to run racing fuel the most likely performance change will be that you'll fuck it.

[caspernz]

Ok heres a one for all you knowledgeable folk!

is high octaine racing fuel normal fuel with shit loads of booster in it, or, is it a more refined cleaner fuel?

Thinking of getting some.

Sssshhh, but last time I delivered a tanker load of AvGas to a facility that decants from 35,000 litres into more consumer friendly sized containers that read "Racing Fuel" it was just that...AvGas.

For any roadgoing vehicle, if you want the highest performance fuel, just use 98 to save yourself the hassle of engine dramas...like Ocean1 already mentioned :niceone:

[baffa]

Do you mean trying 98/95 over 91? I wouldn't bother unless your bike is designed for 95. Octane rating relates to the fuel's ability to self-ingnite under compression. Higher octane being more resistant. I don't think the higher octane is any "cleaner" or "refined".

I hope you arent running your CBR on 91.

Any vehicle with high compression or a turb should be running 95+.
Even slightly nanaspec cars made in Japan are designed to run on higher octane.

There was a great article by the self appointed Gods of motoring, the AA recently basically saying anything greater than 91 is a waste of time. If you beleive that, you are as stupid as they are.

[Metal Doctor]

i always run all my bikes on the best i can get at the pump, i never use 91.

i was thinking about using racing fuel in the KTM on the dirt, i've heard about some guys using it, and i can smell it when i go riding. A fella told me you can buy it from ardmore air field or a service station in pukekohe sells it. apparently some guys mix it 50/50 with 98ron, and someone told me you need a racing licence to buy it! i have no idea if any of this is true!

so is high octain racing fuel and Avgas the same thing then?

[Metal Doctor]

Anyone ever used that octain booster stuff you get in a bottle and mix with your fuel???

[cave weta]

Any difference can only be in the additives, usually well less than 0.01%, and usually arriving in the same container, from the same supplier. You work it out.



I use the one with Techron in it- you know that it actually cleans your car as you drive!- fuckin amazing technology -and it is no dearer than that ordinary shit that the other companies sell.....:bleh:

[Metal Doctor]

I use the one with Techron in it- you know that it actually cleans your car as you drive!- fuckin amazing technology -and it is no dearer than that ordinary shit that the other companies sell.....:bleh:

haha, i should get the missus to put that in her car! maybe it wont look as shit after a tank full!

[Damantis]

i always run all my bikes on the best i can get at the pump, i never use 91.

i was thinking about using racing fuel in the KTM on the dirt, i've heard about some guys using it, and i can smell it when i go riding. A fella told me you can buy it from ardmore air field or a service station in pukekohe sells it. apparently some guys mix it 50/50 with 98ron, and someone told me you need a racing licence to buy it! i have no idea if any of this is true!

so is high octain racing fuel and Avgas the same thing then?

Doesn't that mean the bike isn't burning all of it?

[caspernz]

Doesn't that mean the bike isn't burning all of it?

Nope. Just think of the smell of clean, dry firewood versus old socks. Both burn, different shall we call it odour :laugh:

[Ocean1]

i always run all my bikes on the best i can get at the pump, i never use 91.

The best fuel you can get for your bike is the one it was designed to run. The dudes that decided what compression rate, ignition timing, valve timing, port configuration and a few more design criteria your engine should have knew what they were doing. Read your manual.


so is high octain racing fuel and Avgas the same thing then?

High octane racing fuel isn't a fuel standard. Avgas is. It'squite likely that anyone selling something called high octane racing fuel is, in fact providing something that meets the industry standard definition of avgas.

[Damantis]

Nope. Just think of the smell of clean, dry firewood versus old socks. Both burn, different shall we call it odour :laugh:

Sorta like the difference in smell between Hot Stripper Panties and Homeless, Street-walker Panties. I get it now.

I've run my CBR on 91, 95 and 98 and while there seems to be a tiny bit more acceleration / oomph on 98, the fuel economy is pretty much the same kms per tank only a little more expensive to fill. I use 91 most of the time and give it some 98 when I know I wanna go fast ( at the drags or a trackday of course :msn-wink: )

[caspernz]

Sorta like the difference in smell between Hot Stripper Panties and Homeless, Street-walker Panties. I get it now.

I wouldn't know about that...I'm married :confused:

[FJRider]

I use the one with Techron in it- you know that it actually cleans your car as you drive!- fuckin amazing technology -and it is no dearer than that ordinary shit that the other companies sell.....:bleh:

Does it do the windows too ... ??? :confused:

[Berries]

Works fine on my frying pan.

[Brian d marge]

Get a glass jug and put a litre in. Sit and watch it for a bit.
Look at all the wafty goodies wafting away.
Bye Bye exciting wafty bits. Hello stale remaining bits, I guess its just you and me now the excitment has left

hours of fun in winter ,

Stephen

[Brian d marge]

Octane booster? It's simply one of the chemicals that usually make up petrol anyway, they just add more of it. Octane ratings are largely bullshit anyway, a calculated performance value, rather than any level of "goodness". Even ACTUAL Octane rates are simply indicitive of another more accurate performance value, knock rate, which is the actual range of conditions that the fuel will detonate at.

Racing fuel has a slightly higher knock rate, and because of the additive used to make it that way it's not strictly speeking "lead free".

And unless your engine is specifically designed to run racing fuel the most likely performance change will be that you'll fuck it.
shhhh

They wont believe you , and if you add that most Jap engines are designed to run on 91 , which in asia is about 80 , 85 mon ( or RON cant remember off head ) , and then if you get oil.water leaks into the head from any source , WEEELL you can kiss good bye to the preiviouse rating !!!

Stephen

ps , you wont fk the engine it just will run at a differing temp/ loading , which affect ( effects?) component life ( a little ) ...

Ever seen a seen an brit single exhaust pipe glow red ...hehehehe

[ac3_snow]

i always run all my bikes on the best i can get at the pump, i never use 91.

i was thinking about using racing fuel in the KTM on the dirt, i've heard about some guys using it, and i can smell it when i go riding. A fella told me you can buy it from ardmore air field or a service station in pukekohe sells it. apparently some guys mix it 50/50 with 98ron, and someone told me you need a racing licence to buy it! i have no idea if any of this is true!

so is high octain racing fuel and Avgas the same thing then?

I have used av/racing gas in my 2t bucket, after melting the top of my piston I wanted a bit more insurance against det. Brought it from the mechanics behind shell next to waikaraka park in Onehunga. Cost $4.20 a litre though!
Have since gone back to using 98 as turns out my problem was just the wrong temp spark plug and I have noticed no difference performance wise between the two, maybe if I changed the compression again I would consider the extra cost.

From my understanding there is generally (very slightly) different ignition timing required for an engine to run at optimum on different fuels.

[Hoon]

I used to get my avgas from the servo just before Pukekohe Race track. From mem it was about 20% more expensive than 91/95. That was for my high comp 2-stroke race bike. My 4 stroke race bikes I just use 91.

Another issue with stale fuel is that its knock factor (octane rating) can be reduced causing detonation. Driving down the line one weekend in my car almost out of gas I pulled into some Ma & Pa gas station and filled up. Got a few mins down the road and my engine overheated and cut out. Had the stereo up and didn't realise it was detonating (felt it was a little low on power but just gave it more gas in my ignorance). After waiting ages for it to cool down and replacing all the water in the radiator (at the time I just thought I must have been low on water) it ended up doing the same thing again a few minutes later. Basically had to limp around until I eventually diluted enough of the gas in my tank with proper petrol for it to go away. Damn shit fuel almost destroyed my engine!

[F5 Dave]

I have used av/racing gas in my 2t bucket, after melting the top of my piston . . . .
Have since gone back to using 98 as turns out my problem was just the wrong temp spark plug . . ..
Ahh, the sun comes out & the truth is read. Sure it wasn't that crappy old oil you were using?;)

[F5 Dave]

Sssshhh, but last time I delivered a tanker load of AvGas to a facility that decants from 35,000 litres into more consumer friendly sized containers

And that would have been- where?

Getting harder to find Av in wgtn as Aero club will no longer sell it as some dick head was storing large qtys of it for some dumb reason.

[caspernz]

And that would have been- where?

Getting harder to find Av in wgtn as Aero club will no longer sell it as some dick head was storing large qtys of it for some dumb reason.

Chempro in Seaview. They decant for various suppliers. No sales from their place as far as I know. Basically a bottling facility.

[ac3_snow]

Ahh, the sun comes out & the truth is read. Sure it wasn't that crappy old oil you were using?;)

There is nothing wrong with castrol tts! Haha and at 25:1 there is a very slim chance of failure (haven't even fouled a plug yet).

What I did learn tho is about the heat ratings on spark plugs and how they work. turns out i wanted a B9ES not a B6ES, combined with running a little lean on the main = disaster

[Flip]

Firstly very little of the fuel in this country is still in spec by the time it is sold. It might be fine when it leaves the refinery but by the time it is shipped, had the water removed, blended with the slops from the terminal, transported by road tanker and dropped into the retail tanks and again had the water removed it usually fails on either water or total contamination.

It would be easy to filter the fuel at the point of sale but the 7 sisters, firstly don't want to admit that the fuel is rubbish and also don't want to incur the costs of having to do so many filter changes.

Why do they filter aviation fuel just before they fill airplanes? Because it picks up contamination being shipped and stored. Where do you think the dirt that collects in your glass fuel filter comes from and its only a 100 micron strainer? It doesent grow magically in your fuel tank.

Oh stale fuel, the wee small volatile easy to ignite molecules evaporate and whats left won't ignite with your crappy ignition system. After ages and ages the fuel oxidises and turns to varnish, espcially in carbs.

[caspernz]

Firstly very little of the fuel in this country is still in spec by the time it is sold. It might be fine when it leaves the refinery but by the time it is shipped, had the water removed, blended with the slops from the terminal, transported by road tanker and dropped into the retail tanks and again had the water removed it usually fails on either water or total contamination.

It would be easy to filter the fuel at the point of sale but the 7 sisters, firstly don't want to admit that the fuel is rubbish and also don't want to incur the costs of having to do so many filter changes.

Why do they filter aviation fuel just before they fill airplanes? Because it picks up contamination being shipped and stored. Where do you think the dirt that collects in your glass fuel filter comes from and its only a 100 micron strainer? It doesent grow magically in your fuel tank.

Oh stale fuel, the wee small volatile easy to ignite molecules evaporate and whats left won't ignite with your crappy ignition system. After ages and ages the fuel oxidises and turns to varnish, espcially in carbs.

Sssshhhh!! You're giving away the insider info again :pinch:

Not arguing with your info as it's correct, even if it is a worst case scenario.

In practical terms, if you're up to date with your maintenance on your bike it doesn't matter that much where you buy your fuel from...although personally I avoid the one horse towns simply on the notion that their throughput is small.

Aviation fuel is filtered at point of fuelling the jet yes. BUT, keep in mind that this is partly because of the huge amount of fuel consumed, thus any contamination at all will rapidly have the plane looking for the breakdown lane...typically a cornfield at ground level... So a jet will consume something like 150,000 to 200,000 litres of JetA1 from Auckland to London, so that filter best be up to the job. Now I like to clock a few kays, but I've not had a bike that's consumed that much in its lifetime, let alone in 24 hours...:eek5:

[pouakai]

I once had a tank hanging on the wall for maybe 3 or so years with a little fuel in it. When it came time use it again I was cleaning it out and unfortunately dowsed my hands in the stale petrol. It had turned very brown and smelt very bad. While normally I suffer no ill effects petrol exposure on my hands (not recommended nevertheless) after this quick splash I was sick for a week !!
I don't know what go stale about it but something had very much changed! Taught me about solvent exposure though! (that and the death of my painter's son from solvents!)

:|
P


Depends on the volume, if you have a full tank, it'll last for months with no change (I do this with pre-mix for my dirtbike and 3 months is good). Only a few liters in the tank and a month or two could see it turn to shit. The carb fuel goes off quicker, but you get fresh stuff through quickly so no bother, and it'll take ages to turn to varnish.

I'm sure there is some chemical explanation, but the practical one is enough for me.

I've never had stale fuel in a 4T, but my 4Ts are generally used weekly, had it on my 2T dirtbike, felt like it was 'hunting' for the powerband but couldn't quite find it.