Losing Oil

[erkishhorde]

Wow, it's been a while since I've been in here and I don't miss it.  

Yesterday I had ridden about 65mi on the freeway and didn't notice anything wrong with the bike. Then just before I got off of the freeway the bike felt like it was losing power. On the offramp the bike backfired a lot on deceleration and for a couple blocks it sounded like I was riding a dirt bike and had hardly any go. After sitting at a long stop light it seemed to perform better and sounded normally but wasn't great. After parking for a while it seemed fine and I had no problems on the way home but acceleration around 70 felt weak. I broke the return trip up into 2 segments but not because I noticed anything horribly wrong.

Then today I noticed that I'm out of oil. Like, nothing in the sight glass outa oil. I had just topped it off 2 weeks ago. The bikes been eating a bit of oil for a while now but not like this last batch. I had always thought I was losing it to that tiny leak I've got on the front that I can't track down but It's never leaked enough to leave a puddle on the floor. It just makes a mess on the front of the engine.

Any thoughts on where I should start? On a side note, I guess it's a good time to track down that vacuum leak that I think I have and have neglected for a loooooong time.  

Oh yeah, '95 m900 w/ a shade under 70k miles.

[booger]

Running a 70k engine out of oil...hmmm. I'd start by tearing it down for a rebuild. 

[erkishhorde]

Sounds rough... Can I do it myself or will I need to drop it off at a shop. (ie. special tools)

[avizpls]

oh, special tools are involved for sure.

[erkishhorde]

Bugger. I've got a bucket full of time to put into it but only a shot glass full of coin.

What do you actually mean when you say "rebuild"? What does it entail?

[Speeddog]

Bugger. I've got a bucket full of time to put into it but only a shot glass full of coin.

What do you actually mean when you say "rebuild"? What does it entail?

Before you embark on a possibly needless journey....

How much oil did you add to get it back up to the normal zone in the window?

If you haven't done that, well, do that first.

Is the oil pressure light working?
Did it come on while you were riding?

[erkishhorde]

Was holding off on that in case I had to open the engine. Didn't wanna waste a quart of oil. I'll do it now. I don't recall the light coming on.

Edit: a little more than 1/2 quart. Now that I look at my records, it's about time for an oil change.

[Speeddog]

Pull the spark plugs out, see if they're oily black.

Throw in a new set if they look suspect.

Go out and run it.

Report back.

[Cloner]

Agree with Speeddog.  70k sounds like a lot on an aircooled Duc, but I've see one with 200k on it that still ran on its original pistons!  Don't go digging until you know, or at least reasonably suspect, what's wrong.

[erkishhorde]

Pull the spark plugs out, see if they're oily black.

Throw in a new set if they look suspect.

Go out and run it.

Report back.

Plugs are actually a little white on the tips.  I'll take it out for a scoot tomorrow morning when it's a little cooler.

[bikepilot]

Sounding like a dirt bike and having little power probably means one cylinder wasn't firing.  This could be as simple as bad plugs/wires or coil connections.  Being less than 1qt low shouldn't have done any damage or caused the poor running - the sump pickup is quite low.  It might have caused slightly hotter-than-usual running, but nothing that would have done damage.  Still worth keeping a closer eye on it of course. If both plugs continue to look whitish (not unusual, though a light tan is ideal) chances are the oil isn't getting burnt up in the motor, but is just leaking a bit faster.  What sort of crank case breather does your bike run?  You might explore that a bit to see if its maybe pushing a bit more than usual out that way - if the highway run was at particularly high rpm this is a particularly good place to start.

good luck!

[booger]

I was being facetious. Of course replacing the oil lost would be the place to start. Crossing your fingers and hoping for the best is next - or would fixing that neglected vac leak? Think that might have anything to do with the poor running?  

My experience tells me that any loss of oil pressure whilst running the engine under load compromises the engine to varying degrees. There is nothing special about Ducati engines enabling them to endure abuse that would damage other engines. 200k on original pistons is only possible on bikes that have been taken care of. As in religiously. No offense but that doesn't really sound like the case with the OPs bike.

I'd assume damage. Would I tear into it at this point and look for damage? No. That's expensive and time consuming. I'd source a good used engine before I went that route. The damage done may be inconsequential. Then again it may have shortened its life by a significant amount. The world may never know; it's 70k old as it is. I guess you'll know for sure when you hear a bang and see a connecting rod pokin' out of the side of the motor.

People do get lucky though. Dodging bullets is the exception and not the norm so don't take it for granted. Keep some frickin' oil in the crankcase!  

[Langanobob]

^

I think you may have missed the part where it turns out he was only half a quart low on oil.  That's not going to do any damage.

My guess is that the engine problem is a fuel filter issue or something else but unrelated to the oil level.

[avizpls]

I was being facetious.

as was I

[bikepilot]

Even a full quart low won't cause loss of oil pressure.  Now maybe there's engine damage that caused the loss of oil in the first place.  But running around for a bit at < 1qt low won't have hurt anything.  The sump pickup is quite low in the sump, it'll maintain pressure until its almost out of oil.