Oil level rising....

[Philly_Chris]

Last weekend i found my bike tipped over. Gas had leaked out(from the fill cap), and when I checked the oil level, it was higher than I remembered it. This was odd since it usually is a little lower from a slight leak. Anyway, I changed the oil immediately to make sure it wasnt gasoline that had leaked into the crankcase.
I thought that was the end of the problem, but I took it out for a ride today and when I checked the oil level it was just up above the top of the sight window- higher than I filled it up. The oil might smell a bit like gas- its hard to tell what is normal, i mean it is in the combustion chambers with gasoline.

Is there a way to test for a problem with either the petcock or the float needles? Any other reason my oil level seems to go up? Theres no sign of fuel in the air box and i've never noticed a problem like this before.

Thanks for any ideas

Chris

[Anonymous]

ILL BET THAT THE GAS LEAKED IN WHEN THE BIKE WAS TIPPED OVER

[massakins]

Best way I know to ensure that gas isn't leaking into the motor via the carbs when parked is to disconnect the line from the petcock. Be sure to check the level at the same place every time, same way, to avoid procedural variables. Also possible when the bike tipped that excess oil was in the head around the cams and returned once it was started, but this seems kind of far fetched. Good luck.

[Anonymous]

The oil level can go up if your rings are not so good and there is excessive water vapour (byproduct of combustion of hydrocarbon fuel) getting in there. This happens more often in winter and on short rides as the motor takes longer to warm up and the water vapour condenses more easily, and the oil does not warm up enough to evaporate it off again.

You can tell if you are getting excess water vapour by looking under the oil filler cap for any white/yellow gooey stuff. That's an emulsion of oil and water.

Kim

[Anonymous]

If the engine oil is getting aerated somehow, that would give you a high reading, but it should settle once the engine has been shut down for a bit.

[Anonymous]

Two things to consider, that you might already have considered:

Unless your bike is parked in exactly the same spot on each occasion (and I mean exact - like outlining where the centerstand posts meet the ground) it can change the apparent level of the oil in the sight-glass. Because the centerstand posts are only inches apart, a small dip in your floor can tilt the bike a couple of degrees side-to-side one way or the other. Those sort of dips are not easily discerned while you're upright, but are common on concrete floors and others. Any time I get paranoid about my oil level, I throw a level on my luggage rack to see if the bike is leaning too much.

The other variable would be the temperature of the oil itself. I've no idea to what degree the thermodynamic properties of oil would effect it's volume, except that usual physics, and the chemistry of the oil itself should cause the volume to increase when hot. I believe I see a noticeable difference in the sight glass level hot and cold, so I'm careful now not to put in too much new, cold oil after draining the old. I check my oil level at the end of a ride for consistency purposes, but if I forget when the bike is hot I can still see lots of oil in the sight-glass before my next ride. I like to have the oil level at the full line when hot.

As to a possible petcock or float needle problem, do a search of this forum, because diagnosing and fixing this problem should be well covered in the old posts. If the info has been lost in cyberspace during the webhost-hopping, let us know.

Good luck.

[saaz]

You may have a petrol leak leading to the problem. The water vapour problem usually comes about when the oil level seems to fall a lot aafter a highway run if you usually do shor trips (the water vapour hids the oil consumption but evaporates when hot).

You also have to take the oil reading in the same place or on very level ground if you do thereading on the sidestand. Also, do the reading at the same time after shutting the bike off (or at the same time, eg overnight) at the levels may vary slightly. This variation may be accentuated if you have an oil cooler.

[Anonymous]

I had the same problem on my 1980 GS1000G. It was gas. The fuel petock doesnt have an off on my bike,It relies on the vacuum. I replaced the gasket and o-ring inside. End of problem for less then $20. My carb obviously leaked as well, but you should never rely on the carbs to stop the flow of gas for any period of time (over night).
P.S. when put back together make sure the vacuum release hole lines up to allow the fuel shut-of to close, if you have a vacuum operated fuel petock.

[Carter Turk]

Oil Rising

I'd say the tip over caused one of your float needles to hang up causing slow leakage into the engine. Or a bit of debris worked its way in there.

I'd check to see if there's a wear ring mark around the the needle where it seats or residue in the little screen below. This would increase your oil level overnight.

The rebuild kits cost about $30 a carb, but are a lot cheaper than replacing the whole engine from thin oil. Carter

[Anonymous]

I was reading my son's ground school aircraft flight manual today (raining here), and learned that in cold weather pilots of small planes introduce raw fuel into the lube system by way of a cockpit control a minute before shutdown in cold weather. The thinned oil aids cold weather startup, but the book notes that some pilots choose to do this in all weather because the fueled-oil carries carbon and sludge to the oil screen that would otherwise remain in the engine. This necessitates more frequent maintenance of the oil screen. After having thinned the oil, it is recommended that the aircraft engine be brought up to operating temperature on the ground so as to vaporize or "boil off" the fuel via the crankcase breather. It states that most aircraft engine manufacturers recommend this procedure when temps reach 5 C or 40 F. My reading about aviation gasoline is that it has more, not less, additives than motor vehicle gas. I guess we don't have to panic too much when we learn that there has been some fuel in our crankcase!

[twhite]

I've seen this happen with vehicles before when it wasn't fuel diluted oil...but accidentally overfilled with oil.

The owner would add oil because it appeared low after running to warm up, but in fact the oil just was slow to return to the crank case due to partially clogged passageways, thus appearing low. The oil in effect would get trapped in the top end and slooowly drain back to the crankcase, but the owner had already added more oil to the engine.

Took the valve cover of a small block chevy that must have had a quart or two "trapped" up top, what a mess.

[Anonymous]

I've seen this happen with vehicles before when it wasn't fuel diluted oil...but accidentally overfilled with oil.

Okay, I gotta tell you about my life-long friend Fred (not a friend of a friend who knows a guy). He has no idea about things mechanical, never learned to ride a bicycle, much less a motorcycle. Born to money, his parents have handed down to him, free, every auto they've owned for 30 years. Including one three year old car, the first auto he owned after moving out, so dad wasn't in a position to maintain it for him. The very first times he checked the oil himself he put in numerous litres, then couldn't get the car to run. Expensive repairs ensued. He sheepishly admits to having checked the oil level incorrectly and filling the engine with enough oil to cause hydraulic lock on the bottom end. His dad later admitted to me that he had apparently been mistakenly checking the transmission fluid level.

[focus frenzy]

I've seen this happen with vehicles before when it wasn't fuel diluted oil...but accidentally overfilled with oil.

The owner would add oil because it appeared low after running to warm up, but in fact the oil just was slow to return to the crank case due to partially clogged passageways, thus appearing low. The oil in effect would get trapped in the top end and slooowly drain back to the crankcase, but the owner had already added more oil to the engine.

Took the valve cover of a small block chevy that must have had a quart or two "trapped" up top, what a mess.

yes, the cadilac small blocks (4.1-4.5) 16 valve v-8's are bad about being slow to drain down, also the class 8 trucks that I work on take around 15 minutes to drain all the oil back down to the crankcase. (they hold up to 40 quarts of oil, and often show up to 8 quarts low, when they have been just shut off)

[earlfor]

Reminds me of the DC-3's I used to service. Some of them held
60 gallons of oil on each engine and they could come in hot and before the accumulator tanks had time to drain, they could show 20 0r 30 gallons low. :-) :-) :-)

Earl

also the class 8 trucks that I work on take around 15 minutes to drain all the oil back down to the crankcase. (they hold up to 40 quarts of oil, and often show up to 8 quarts low, when they have been just shut off)