A little gasoline in the oil

[w261w261]

I have a '73 Honda bike, which has the standard off-reserve-on fuel valve. A problem with these old bikes, mine included, is if you forget to turn off the gas and leave it for a period of time, the fuel will gradually leak through the carbs to the crankcase. Enough gets in there, it's hydrolock time, and bye bye engine.

That's why I always check my oil level before I ride, not to see if there's not enough oil, but to see if there's too much! I've only forgotten to turn the gas off a couple of times in 10 years, not too bad.

Here's my question: yesterday was one of the times I've forgotten, but the amount that the oil level went up was very small. Besides hydrolocking the engine, the other concern with diluted oil is the head, which has a very fine-toleranced torsion bar valve spring DOHC setup (pretty good for '73, kudos to Mother Honda). I decided that with a moderate riding style, I hadn't diluted the oil enough to be a problem, and that after a ride of an hour or so, the gas would be evaporated out. After thinking about it a bit, I decided to ask the experts here.....the gas has departed the oil, hasn't it?

Thx

[mephi]

Probably, but it couldn't hurt to change the oil and filter.

[89T]

I have a '73 Honda bike, which has the standard off-reserve-on fuel valve. A problem with these old bikes, mine included, is if you forget to turn off the gas and leave it for a period of time, the fuel will gradually leak through the carbs to the crankcase. Enough gets in there, it's hydro-lock time, and bye bye engine.

That's why I always check my oil level before I ride, not to see if there's not enough oil, but to see if there's too much! I've only forgotten to turn the gas off a couple of times in 10 years, not too bad.

Here's my question: yesterday was one of the times I've forgotten, but the amount that the oil level went up was very small. Besides hydro-locking the engine, the other concern with diluted oil is the head, which has a very fine-tolerance torsion bar valve spring DOHC setup (pretty good for '73, kudos to Mother Honda). I decided that with a moderate riding style, I hadn't diluted the oil enough to be a problem, and that after a ride of an hour or so, the gas would be evaporated out. After thinking about it a bit, I decided to ask the experts here.....the gas has departed the oil, hasn't it?

Thx

I am by no means a chemist, but the fuel mixing with oil would thin the viscosity of the oil. there is a possibility the fuel evaporated, but the chemical make up of the oil has been altered. soooo?

One ride i don't think you ruined the engine but prolonged use will take a toll on rings, bearings and seals.

I thought hydro-lock meant : a liquid trapped between the piston and head.

[Oldblueaccord]

I would hedge on the NO side of that one. I know alotta of my Chevy buddies wiping out cams when the fuel pumps whould fail and dump oil into the crankcase. Not that I dont like your theory I just hate to bet a motor on it.

wp

[2oodoor]

I would hedge on the NO side of that one. I know alotta of my Chevy buddies wiping out cams when the fuel pumps whould fail and dump oil into the crankcase. Not that I dont like your theory I just hate to bet a motor on it.

wp

ditto, you are caramelizing with that contaminated oil, good when it is in a cook pan .. bad for engines

[w261w261]

Changed out the oil today, thanks guys.

[mephi]

In my experience, it usually takes a lot of time for fuel contaminated oil to cause damage, but I personally like changing it out as soon as I notice any problems...Since you changed it, you should not have any.

[cubert]

i highly doubt you did any damage to the engine. Ive ridden bikes with so much gas mixed in with the oil the bike turns into a smoke machine


No issues after changing the oil and filter though.


Oh..and glad to see im not the only one here running a really old streetbike