How long does petrol last?

[Easy Rider]

Originally Posted by alantf

A good upper cylinder lubricant?

Yes. As long as the oil isn't more than a couple of years old.
2-stroke oil doesn't have many "additives" in it so it lasts a long time.
About 1 ounce in a whole tank would be about right, I think.

[dentheman]

What will this oil/gas mixture lubricate that isn't already being sufficiently lubed by the bike's oil system?

[Water Warrior 2]

Originally Posted by dentheman

What will this oil/gas mixture lubricate that isn't already being sufficiently lubed by the bike's oil system?

The inside of the gas tank and carb come to mind. Really doesn't matter in the grand scheme of things. The bike is well enough designed to lube what needs to be lubed.

[Easy Rider]

Originally Posted by dentheman

What will this oil/gas mixture lubricate that isn't already being sufficiently lubed by the bike's oil system?

Well, if you are going to be practical about the whole matter.......and throw around qualifiers like "sufficiently"........... :biggrin:

The answer is: Probably nothing. The standard answer from those who advocate doing such a thing is: The valve seats, upper valve guides and the top piston ring. I doubt that any of those things really NEEDS any additional lubrication......unless maybe you are trying to get something like 3 million miles without a rebuild !! :roll:

[dentheman]

So I surmise that adding an ounce of 2 cycle oil to a full tank gas on a GZ won't hurt anything and might be beneficial in the long run. But I also think that adding oil to gas on something like a TU250 would damage the catalytic converter/ oxygen sensor. Perhaps the fuel injector too.

[Easy Rider]

Originally Posted by dentheman

So I surmise that adding an ounce of 2 cycle oil to a full tank gas on a GZ won't hurt anything and might be beneficial in the long run. But I also think that adding oil to gas on something like a TU250 would damage the catalytic converter/ oxygen sensor.

Yes and yes.
Possible in the first case and very likely in the second.

Something like MMO (Marvel Mystery Oil) is actually intended for that purpose.....but I personally would not use anything like that in a modern FI vehicle; too big a risk for such a small and unmeasureable benefit.

[dentheman]

Originally Posted by alantf

Don't waste it! Have you got a car? If so, when you've used up 5 litres of a full tank, add this canful. Should be o.k. mixed with the 30 to 40 litres already in the tank. :2tup:

I would be leary of putting that old gas in my car. Once gas has sat that long in a can there will probably be crud on the bottom of the can. Thats my experience with a gas can used for my lawn mower.

[alantf]

Originally Posted by dentheman

Once gas has sat that long in a can there will probably be crud on the bottom of the can.

If he's talking 5 litres, then I imagine he's talking about the plastic cans used in England/Ireland, & specific for storing fuel. black for deisel, red for leaded petrol, green for unleaded. They are specifically designed for fuel storage, & don't rust/shed gunge like the old metal cans.

[dentheman]

Originally Posted by alantf

If he's talking 5 litres, then I imagine he's talking about the plastic cans used in England/Ireland, & specific for storing fuel. black for deisel, red for leaded petrol, green for unleaded. They are specifically designed for fuel storage, & don't rust/shed gunge like the old metal cans.

Mine is a red plastic can designed for gas, it still gets crud on the bottom.

[alantf]

Originally Posted by dentheman

Mine is a red plastic can designed for gas, it still gets crud on the bottom.

Dunno, but this seems to suggest that there was crud in the petrol before you put it in the can, & it sank to the bottom over time. :??: