oil question

[Shockman54]

well, while tearing the engine apart on my 81 xs special, i noticed that the oil i drained was very thin. it seemed like there was a lot of water or something in it ( i don't think it was gas, didn't smell right.) it was about 35 degrees out, and the other oil i've drained from my 79 was much thicker at the same temp. anyone have any idea why that is?

[DGXSER]

First, did you put the oil in it? Is it possible someone put 5W20 in it instead of 20W50?

Otherwise, the most likely answer remains gas in the oil, depending how long it has sat the vapors which give the odor may be gone.

[ViperRon]

Did you by the chance check the level of the oil before you drained it? Usually when gas gets in the oil the level will increase. If the oil put in it was a lighter weight oil you would have more than likely have burnt oil causing it to be low. If the oil was in there long enough for the engine to beat it to where it was that thin then when you drained it you should have had dark crummy chuncks come out with the oil and the oil should have been black and smell somewhat burnt. The most likely cause is that you have leaking carb floats and this may be intensified by leaking petcocks or octy.

While you may not now have the answer it is very important to resolve the issue if its gas in the oil. Gas destroys the oil very quickly and can damage all parts of the engine depending on how long you run it.

I would check the filter box and see if you have gas residue in there. I would check to see if the petcocks are leaking. You can park the bike and elevate the front wheel enough and the gas will drain to the rear of the bike if the float needles are allowing gas to flow. There are many threads here on carb's and a lot of information in the troubleshooting and maintenace section on problems, cleaning, adjustments, and repair.

[fredintoon]

well, while tearing the engine apart on my 81 xs special, i noticed that the oil i drained was very thin. it seemed like there was a lot of water or something in it ( i don't think it was gas, didn't smell right.) it was about 35 degrees out, and the other oil i've drained from my 79 was much thicker at the same temp. anyone have any idea why that is?

Hi Bill,
it ain't water.
if the engine has been run with water in the oil the mixture gets emulsified and looks like beige cream.
If the engine has not been run and water has been added to the oil it just won't mix, it will settle out with the oil on top.
Do you know what oil was put in there or did someone else do it?

[Shockman54]

I put yamalube oil in. i don't recall off the top of my head what type, but i know i looked up the recommended oil before putting it in. as far as i can tell, it is gas. the carbs were leaking gas and this bike has another unknown problem (hence tearing the engine apart.) there was also a yellow film over the engine under the carbs. so im guessing the carbs need to be rebuilt. is there any other way that much gas could get into the engine?

[jimbyjimb]

The only liquid this bike has to leak into the motor oil is fuel. Has to be. It can potentially leak past the carbs into the crankcase if you leave the fuel valves in prime or if there is an issue with the vacuum diaphragm(s). A tried and true method is to inspect the spark plugs for fuel fouling after cranking or look into the cylinder bores and smell and look for signs of excessive liquid fuel.

If you know you have carb issues then you've most likely found the culprit.