Weird Oil Behavior

Something strange happened when I was changing my oil this morning. I warmed the bike up for about five minutes, then rode it for another five minutes or so. I put it up on the center stand (garage floor, dead level), unscrewed the filler cap, pulled the drain bolt, and.......only about a pint of oil dribbled into the catch pan. At first I freaked, thinking that was all the oil I had in the case. My fears of engine guts being ground into dust were allayed when I checked the window guage, and it showed there was still plenty of oil in the bike.
I tapped the starter to turn the crank, and some more oil burped out but immediately stopped flowing again. I repeated the tap-and-burp process until all of the old blood was out. I've changed the oil on this bike many, many times, and this has never happened before. Ordinarily, I pull the drain plug, and the entire 3+ quarts spills right out.
The old oil was nice and clean--no metal shavings or anything else that looked suspicious. The bike runs perfectly, with no unusual noises or glowing idiot lights. What gives? Should I be worried?

 

I'll bet you removed the oil filter housing retaining bolt rather than the oil pan drain bolt............the large drain bolt is in the front of the oil PAN, directly below the small (12mm stock) oil filter cover retaining bolt.

 

Nope. That ain't it. I'm wondering if the strainer on the sump is clogged, and if so, why?

 

Hmmmmm.....well, I lost that bet! You may be right, and that sure would qualify as a weird oil problem......!

 

Did you have the fill cap off? If not maybe a vacuum builds on the inside of the case? Just a guess.

 

Dropping the sump on this bike is going to be a major pain, but I guess it has to be done. I can't think of another likely cause. Strange that the pressure light wouldn't go on in this situation, though.

 

What did the oil actually look like once out? Jello? Sometimes a combo of things (crap oil being the first suspect) causes the oil to gell up..
Dunno, the cause of your poeoblem..just guessing .

 

That would be because we don't have oil pressure lights -- we have oil level lights

Sounds like something is blocking the drain hole -- some kind of grunge or something? Might be time to take off the oil pan for a full cleaning....

 

Go get a thin cylindrical "Magnet-on-a-stick" and probe the Drain Hole for metal Filings.

Can Opener the Oil Filter and spread-out the filter element and run a strong magnet over the filtering medium.

If you have metal filings in the Oil Filter ... you're got trouble brewing in there someplace.

Was there a big clog of Chia Pet looking-like filings on the Drain Plug magnet?

 

No filings anywhere, thank God. I'll drop the oil pan when I finish work this morning and see what I can see.

 

This is a scary story- keep us posted!

 

I finally got a chance to remove the oil pan (sump) today, and I wasn't too pleased with what I saw. There was a fair amount of sludge in the pan, and some on the oil pick-up screen as well. I don't know where it came from, because I'm fanatical when it comes to changing the oil (every 4-6 weeks or 1500 miles, depending on how much riding I'm doing).
I did have a petcock problem last year which was causing fuel to be dumped into the crankcase, but I caught it early and corrected it immediately. I live in the city, and my commute to work is only about six miles these days. As a result, the bike is subjected to lots of short trips and a fair amount of stop-and-go traffic. I also tend to ride high in the RPM range, because that's where the power is on this bike. Still, given the frequency of oil changes, and the bullet-proof nature of these motors, I don't see how the sludge build-up could have occurred, unless the PO completely neglected the bike. Even if that were the case, you'd think the problem would have shown itself earlier.
So the question is: what to do about it. As of now, there are no obvious signs of damage. There were no metal filings evident in the old oil or filter, and the engine runs perfectly. The bike doesn't smoke or burn oil. Should I leave well enough alone? Would using a flushing oil on a 27-year-old bike do more harm than good?

 

spray down what you can see with some cleaner and get the gunk out that will fall out of the motor. Def clean the pickup screen out. If you ran any kind of flush be prepared to change the oil frequently for the next week. I have heard seafoam isn't too hard on them in the crankcase but don't drive the piss out of it with any cleaner in it take it very easy if not just on the stand running then drop the oil out of it.

 

I'd say it sounds like the PO used crappy cheap oil and built up sludge in the engine. Now your use of good oil has loosened it, causing it to build up in the sump.

As long as there's no metal or foreign objects in the oil, I'd say you don't have to worry about damage at all.

Doing a full engine oil flush would be a good idea I think - flushing won't cause any problems, and then you know you're starting again from a pristine clean engine.

 

Working on an old bike that the PO trashed.... So I want to clean up the internals as much as possible before I fire her for the first time (still at least a week or two away)..

I am a novice here, how exactly do you do a flush?? and what do you need/use??

thanks!

 

Remove the sludge.
Sludge retains heat, makes oil break-down and multiplies.
Go ahead and clean-out the sump. Your bike will be better off for it.
Be sure the Oil Pump Screen is nice nd clean; too.

The only reasons I can come-up with for the sump being full of sludge is the PO not doing any Oil changes with any regularity ... or, some blow-by due to compression difficulties.

The blow-by gases help to form the sludge.
Regular Oil changes prevent its build up.
I guess that tells the story about how well the PO cared for the bike.

Now, you have it and its cleaned-out and freshly oiled.
If there no damage done you got to it in time.
Good news.

 

Here is an interesting thought. I might get shot for it, but here goes. What would ahppen if a person drained the oil out, put the plug back in, and poured some gasoline into the engine. Let it sit for a coupel of days, and then drain it out, and add the right amount of oil. Run it for a few minutes only, and then do another oil change. Any thoughts of what that would do to the engine? I'm thinking the solvents in the gasoline would dissolve most of the grime. I'm also thinking that the gas wouldn't do much harm in there if it wasn't run in there. Thoughts? Dropping the sump ain't no fun for sure!!!

 

I did my first "diesel flush" 25 years ago. I even ruined a VW motor that was held together by sludge, and leaked terribly from pushrod seals, covers, Etc. after that trick. So in the spirit of trying not to damage the valuable XJ engine, let's not over-do it.

You can drain about half of an engine's oil, replace with diesel, or "store bought" motor flush, run the warm engine for 5 min, let sit an hour? run 5 min, drain, and filter change. Not recommended to drive a motorcycle with thin oil, but I have put the diesel in a car AT THE PUMP ! then drove home.

And how about working in a 20 minute ride home? That might help fight the sludge, or at least make you feel good !!

 

I ran diesel in an old Bonneville years back, didn't do squat for the top end but did flush out some of the crud from underneath. I'd be sure not to put any engine with diesel in it under load, you'll ruin the lower end bearing for sure! Diesel just isn't enough to protect the bearings against the shear and pressure. Use a reputable engine flush and see what joy that brings you.

 

Kerosene or (even better) Seafoam in the oil works best. I've heard of people using transmission fluid in the oil too as a detergent to get crud out, but I prefer the Seafoam now. Run the engine for a while with that in there, drain completely (leaving it to drip for a couple hours) - don't forget the middle-gear drain if you're doing a flush. Then add a new filter, refill with good oil, and you're good to go.

 

If you remove that Middle Gear Drain and break it to let 27 cc's of fluid drain out of the Middle Gear you will be cursing the day for ever more.

What's in the Middle Gear cavity will change itself seconds after the engine is started.

It is not worth the risk to touch the Middle Gear Plug.
If you do ...
And it breaks ...
You have boat-load of work to do to correct the problem.

I don't recommend fooling around with the Middle Gear Drain Plug for any reason what-so-ever!