Hypothetical oil question.

Suppose I had just filled my wet sump bike with lovely fresh clean oil. Then a short time later I found a couple of litres of gasoline had decanted in there from the fuel tank.
Could I drain the oil, boil/evaporate off the petrol, then stick the oil back in the sump and ride on with impunity? Would it likely have changed the oil constituents detrimentally?

I appreciate that there are hazards to health implied here. I’d be sure to wait until the missus was out for a lengthy time before sticking it all in a saucepan on the kitchen stove.

Butch, put your hand in your pocket and buy some new oil. The fire service are hard enough pressed without you adding to their worries! :smiley:

Get yourself a 2 stroke & use it in that !!

Got a two stroke, but I value the motor on that more than I do the one this ‘premix’ might hypothetically be in. Garage has an asbestos roof, so I should be OK - right? And obviously I wouldn’t be stupid enough to be smoking my pipe whilst I were doing this.

But are there any chemists here with a view ?

Actually I did think of setting fire to it, but thought maybe best not mention - be interested tho whether indeed the petrol could be burnt off leaving the oil behind.


Appendix: I just remembered that the tar byproduct from making coal gas was distilled to separate out its constituents, which were, “light oil”, “heavy oil”, and pitch. (Which the latter was left behind.) That was from an old Open University TV proggie. :smiley:

Unfortunately burning it off will produce soot that will contaminate the oil.

To distill the petrol/oil mix would require more sophistic kit than a saucepan and a thermometer the temperature control is key and to get that right you would need a fractional distillation column (memories of school chemistry). I would also not recommend evaporating off the petrol without consideration for dispelling the petrol vapour which of course is highly flammable.
Still cheaper and safer to buy some more oil.

Thanks folks. It was a bit of amusement anyway.

I guess I’ll dip a pipe cleaner in the hypothetical bike sump tomorrow and see if the level has risen again.

If so I guess it will be another trip to Halfords – hypothetically a purveyor of useful motoring parts and accessories.
And sourcing another pair of petrol taps that might actually limit flow when in the off position.

I have in the meantime been advised on the approach of separating ethanol from gasoline. One for another day perhaps.

Oh and by the way, how is the petrol getting into the sump?

I think the need for working petrol taps was the give away :confused:

Just as I was bracing my self for the “Suspected Fire Bomb Attack in Braintree”. Headline. :smiley:

Well since the great oil spray incident I’ve tested as best I can the action of both taps and the float/needles in the carbs. They seem OK, but gasoline has descended to the sump somehow. To be fair, the taps aren’t sexed so they go opposite ways for off and reserve, so it is possible that on occasion this confused old gentleman hes left the bike with them on reserve rather than off.
But even so …

Anyhoos, I’ve been out there shimming the clutch again. A quick dip of the sump with a pipe cleaner shows all is well with the level. Painted the off positions for the taps on the sides of the tank. Not much use in the dark perhaps, but might help.

Ye-ah, requires A. tap(s) left on or leaking; B. carb needle valve(s) leaking; leading to: C. petrol getting into inlet valves then down past pistons. (?) It’s a bit of a journey…

But if carb needle valves not sealing would be all over the floor?

And sourcing another pair of petrol taps that might actually limit flow when in the off position…
Some years ago…I came ome from work on me V50…parked him up and went to bed…emerging only briefly over the next week…
When I recovered …jumped on me bike and roared off to Market Drayton…got halfway there and the oil warning light came on…
Yep…had left the fuel on…sump full off petrol…blew the pressure switch…

On my loop, I left the taps on and only realised because petrol was dripping out of the left-hand silencer. I assume it must have gone down the inlet and out of the exhaust valve, presumably with the piston fairly near the top. I suppose a bit would have gone down the bore as well, but none came out of the carb overflow.

Quite bizarre. Or seems so to me. :smiley: