SOME...Gas in oil?

[jharvey]

Greetings,


Someone tried to steal my motorcycle overnight two weeks ago [outdoor gravel parking lot behind my apartment building], and in the unsuccessful attempt, left the bike lying on its side for me to find the next afternoon – guessing about 14 hours on its left side.

The left hand mirror and left rear turn signal housing were smashed, and once I got the bike upright, I checked the obvious things – lead acid battery had not leaked and levels between cells remained even, a little bit of gas leaked out of the tank, but surprisingly little, considering it was essentially full, and how long it would’ve been lying on its side - in fact, the only evidence was a bit of a residual trail on the left side of the tank, nothing on the ground at all and no smell of spilled gas. I then took out the plugs and manually rotated the engine a few times from the rear wheel to make sure there was no chance of hydro-lock.

I had ridden it a pair of times since for about an hour each (no problems), when someone suggested I might need to replace the oil in case gas had gotten into the oil while the bike was on its side - telling me that I’d be able to smell it as soon as I removed the dipstick cover. So when I did, so, there was no immediate smell of gas, even if I got quite close to the hole, but if I literally got so close that the tip of my nose was extending into the hole and took a deep breath, I could smell gas - not strong but there. By the same token, I put a few drops of oil onto a paper towel and couldn’t smell anything until my nose was essentially touching the paper towel itself - but I could smell it then. (I suppose, since I never did such a test before, that smell could have been there as a normal thing, even before the bike was knocked over. It would’ve been nice to have had a before, and after ‘scratch n sniff’ test.)

(In case this is relevant, this bike uses a vacuum style fuel petcock – so there are no On, Off, or Prime settings, just On and Reserve. 1980 GS400ET. )

So my question is, would there be at least some trace of gas in the oil simply as a function of oil being in the cylinders during combustion (especially given the bike's age), or should even the faintest whiff require immediate replacement?


Thanks,

[Brendan W]

There will always be gas in the oil. How much and if you can smell it depends on your nose.
Has the oil level risen?
For what it costs, if in doubt, just change it.

[Nessism]

Bummer on the A-hole jerking around with your bike.

As long as the oil level hasn't increased, I wouldn't worry about gas in the oil. At most, there is only a float bowls worth of fuel in the equation.

[Suzukian]

I have never smelled gas in my oil (except when I left it on "PRI" once. I would change the oil, and filter out. Better safe than sorry. Any excessive gas will lower the oil's viscosity and not give your engine the protection it deserves.

[rphillips]

No doubt, any gas in oil will lower the oil's viscosity. A small amount would take special equipment to ever detect, larger amounts will make it as thin as water. Not a clue how much barely enough to smell would do, probably closer to the special equipment end. Could look at it this way, if you hadn't have stuck your nose in the filler hole, you would have never had a question. Personally if I couldn't notice extra in the sight glass I'd not even think about it, But like he said, change it then forget it, Just always remember, it should be in the manual someplace, the filler hole IS NOT for putting your nose in.

[93Bandit]

As others have said, I personally wouldn't worry about it if the oil level hasn't gone up and the smell of gas in the oil is barely noticeable. As others have mentioned, there's always a little fuel in the oil.

I have an old Lesco mower with a single cylinder kawasaki engine. It's an early 90s model and spent at least 15yrs in commercial service before it was retired to part time use on my lawn. I have no idea how many hours are on it, but I know it's a lot and it's never been rebuilt. It has a manual fuel petcock and I forget to turn it off sometimes. I've filled the crank case with fuel a few times as a result. I'm lazy and last time this happened, I didn't bother changing the oil. It had a LOT of fuel in the oil, the dip stick showed it way over filled, and the oil on the dip stick was thin. I've been running it as is and the fuel has been slowly evaporating. This engine has ball bearing crank mains. Not sure what type of bearing the cam uses. No issues whatsoever, although it smoked like the dickens for a while. The thing just keeps running. Obviously this is anecdotal at best. And no, I do NOT recommend running an engine with oil full of fuel. The rest of this mower is shot, completely worn out. The only good thing left is the engine. I've been looking for an excuse to buy a new mower but I'm too cheap to do so until this thing dies, hence why I opted to not change the oil this last time.

I guess my point is, like Ed said, at most you have a carb bowls worth of fuel in several quarts of oil. It's probably fine. On the other hand, oil is cheap and engines are not. You didn't mention how many miles/time you have on this oil change, so maybe its time to change the only anyways?

[LAB3]

It costs about $15 to change the oil if you reuse the old filter, just do it and be done with it!

[jharvey]

Thanks everyone for the input. This is pretty much what I expected, but it’s good to get other, more qualified, opinions that I’m not going to be doing any irreparable damage the next time I start the engine.

In answer to questions about the oil level, and whether it went up. Without having measured it in the immediate days before, I’m as sure as I can be that the answer is no. In fact, I had been getting ready to do two of my spring rituals that weekend - check the oil level and top up, and adjust the idle setting (I have to reset the idle on this bike every winter and spring as the temperatures change and anytime it gets a tuneup – it’s a finicky old bugger), and the oil level was actually about a fifth of the way down between full and empty. (Still old school dipstick on this unit, no conveniences like sight glasses)

But as advised, I’ll get the oil changed anyway when I can shoehorn my way into my shop’s schedule. (Oil changed last September, probably 30-40 hours of running time since then.) For my first 10 or 15 years with this bike I changed the oil myself all the time, even putting heavier weight in the summer and lighter in the winter - until I stripped the drain plug. From that moment, I’ve been paranoid about doing it myself and then having to pay to have it picked up and taken to the mechanic’s to drill out and reseat a new plug

Once stripped, twice shy.

Thanks again, it’s appreciated



(“Just always remember, it should be in the manual someplace, the filler hole IS NOT for putting your nose in…”
I was just waiting for one of the neighbours to stroll by while I was inhaling, especially as I did it several times -after taking some fresh air to cleanse the olfactory palate as it were- just to be sure.)

[rphillips]

Glad you weren't caught in the act...OOhh very embarrassing.

[Suzukian]

I just purchased a set of the quick drain plugs for my ZZR1200, as that bike has a full fairing and you have to change the oil from 2 places, the head, and the crankcase. I leave the plastic tube with the fitting that you just push up and turn to drain the oil. I will be getting one for my Suzuki. I change my oil every 2500 miles or if it feels "now new" on the dipstick. I have 40K on this bike, which I've owned since new. It doesn't smoke, and I do rev the heck out of it, but I don't beat on it. I saw 125 mph on the bike a month ago, solid as a rock. I have just put in a new clutched and was amazed how much better it grabbed, just kept on going till I realized I was in danger of being seen by a Cop. It was mid day, nobody on the road in either direction. An excellent straight section of Rte. 22 in New York, about 20 miles north of Patterson.

[Rob S.]

I thought you got a great deal on it used?

I have been known to change Suzi's oil in as few as 600 miles. If it's going into the shop, the oil gets changed. If the oil gets changed, it gets a new filter.

[jharvey]

rphillips - and just imagine if it hadn’t been my own bike…

Suzukian - that looks absolutely BRILLIANT!! I’ll have to look into that.

Rob S. - Nope, original owner - my first, last and only bike. I bought it in May, 1980 - so it’s 43 and I’m 63. Just a question now of which one of us croaks first.

[Rob S.]

Sorry, I was talking about Suzukian's ZZR1200.

[rphillips]

Rob, that's something I haven't heard before but sure there must be reasoning behind it. Care to share how going into a shop should instigate an oil change.... I feel I've missed something.

[Rob S.]

Rob, that's something I haven't heard before but sure there must be reasoning behind it. Care to share how going into a shop should instigate an oil change.... I feel I've missed something.

Too much money, not enough time.