02 M750 smoking and not starting

[SDKmann]

Posted this on another forum, but this forum looks far more active.

Just bought an 02 M750, first bike I've had since living abroad years ago. On the ride back after purchasing it the low oil light came on and stalled out at one point right as it was being parked (in 1st gear, clutch in, at a complete stop). Since then it's been difficult to start in 1st, but starts pretty much right away in neutral. It will occasionally stall in 1st with the clutch in when I come to a stop while riding, has happened maybe 2-3 more times in the last couple weeks.

Right away after getting it home I added just over 2 quarts of oil, it was definitely low before that point, but now in the oil window it shows fluid almost up to the top hash mark when it's not running. The oil light is still on. For at least a week now I've started it or taken it on a short ride almost daily. Hesitates just a bit starting in neutral, still doesn't like to start in 1st, but will start in 1st after a little cranking. Once it's started it idles consistently at 1k.

Went to go start it tonight and had a lot more difficulty than usual, it was in neutral at the time. When I got it started it idled without dying, but at 500 rpm instead of the typical 1k. After I killed the engine a good bit of smoke started coming out of the exhaust, light grey in color. Didn't seem like anything was off beyond what's been going on from the beginning on yesterday's ride. I do have fuel injector cleaner in the tank right now, and the temperature today is much colder than its been recently. The bike did also fall over in the garage once already, but was quickly picked back up.

I originally thought the low oil light staying on was possibly a bad sensor and the issues with it not liking to start in 1st and occasionally stalling in 1st were due to the computer thinking the oil was still low and going into some kind of limp mode. In addition to the oil light, the word "low" also flashes on the window on the tach side of the gauges next to a temp sign. Again, thought this seemed like a sensor issue until tonight with the increased difficulty to start, low idle, and smoke.

Since I posted this on another forum last night I tried starting it again. Couple attempts didn't get it started, would fire up hard for a split second and die, and didn't want to keep revving it to try and keep it going.

Any ideas on the possible problem from this description? I'll be getting it to a shop ASAP but would like maybe a baseline of what to expect. Hoping that its salvageable.

[Dirty Duc]

The oil light is referencing pressure, not level.  Low oil level can cause low oil pressure, especially when more than half of the oil is missing.

My crystal ball shows me you have an engine swap in the near future. Mostly because it isn't really cost effective to rebuild a 750 that old.

[SDKmann]

Any good sources for a new engine other than eBay that I should take a look at?

[ducpainter]

It sounds to me like you have a fouled plug, which is why the idle dropped, and it isn't starting easily. That could also account for the 'smoke' coming out of the exhaust when you shut it down. It also sounds like your clutch might be dragging. What's it like to find neutral at a standstill?

The oil was low, but is the bike making weird noises?

If you have no service history on the bike, I'd get it to a shop and have them diagnose the oil light, and go from there. If the bike has no oil pressure, then see Dirty Duc's post about an engine swap. Did the bike get wet just before the light came on?

It's possible a full service, belts, plugs, valve adjust, fuel filter, throttle body synch...the works...could put it right. That in itself won't be inexpensive.

[SDKmann]

It sounds to me like you have a fouled plug, which is why the idle dropped, and it isn't starting easily. That could also account for the 'smoke' coming out of the exhaust when you shut it down. It also sounds like your clutch might be dragging. What's it like to find neutral at a standstill?

The oil was low, but is the bike making weird noises?

If you have no service history on the bike, I'd get it to a shop and have them diagnose the oil light, and go from there. If the bike has no oil pressure, then see Dirty Duc's post about an engine swap. Did the bike get wet just before the light came on?

It's possible a full service, belts, plugs, valve adjust, fuel filter, throttle body synch...the works...could put it right. That in itself won't be inexpensive.

Neutral has been difficult to find a couple times now, with the shifter hard to pull up into neutral and jumping to second when it's given enough pressure to move at all.

No strange noises when running, ran well right before this except for occasionally stalling in 1st.

Dont believe the bike has been wet since I've had it, been garage kept onsofar. Good to know there could be a few scenarios and it's not automatically an engine swap on the horizon. Used engines are a lot less expensive than I was expecting though, so that is positive.

[Howie]

If you indeed do have a low oil pressure situation other than slightly low at idle continuing to attempt to run the bike will destroy the engine.  There is no "limp mode" for low oil pressure.

Gotta agree with ducpainter, your bike should be in a good shop.  First step would be getting the bike running with a mechanical oil pressure gauge installed.  Pressure good? Go from there.  Idle speed and power dropping to half, again,I agree with ducpainter, running on one cylinder.  Likely a spark plug, but could also be a coil, wire, ECU or more.

Your hard starting in gear and stalling problem is a separate issue, clutch drag.  Most likely bad clutch slave, or, if you are lucky, a good clutch bleeding.

No service records?  As soon as you know the engine is in god shape a complete service including new timing belts and brake/clutch fluid are in order.

[Dirty Duc]

Ducpainter and Howie know a lot more about these bikes than I do.  It is still possible that swarf from low oil has damaged the engine enough to foul the plugs via oil and cause other issues...

My recommendation is to learn as much as you can about the bike and tackle rebuild issues yourself.... But I also have a tendency to done in on the deep end of projects...

[SDKmann]

It sounds to me like you have a fouled plug, which is why the idle dropped, and it isn't starting easily. That could also account for the 'smoke' coming out of the exhaust when you shut it down. It also sounds like your clutch might be dragging. What's it like to find neutral at a standstill?

The oil was low, but is the bike making weird noises?

If you have no service history on the bike, I'd get it to a shop and have them diagnose the oil light, and go from there. If the bike has no oil pressure, then see Dirty Duc's post about an engine swap. Did the bike get wet just before the light came on?

It's possible a full service, belts, plugs, valve adjust, fuel filter, throttle body synch...the works...could put it right. That in itself won't be inexpensive.

It was the plugs! Swapped them out this morning and the bike is running fine. The oil light comes on when the key is in the ignition but goes away the second the bike is running. Now that I think of it, this may have been happening from day one with it (the light going off once the bike is running).

Obviously still need to get it to a shop but greatly appreciate the help on this one. Hopefully starting now with proper service will keep the bike alive long term.

[GK]

Glad the solution was cheap and easy! ðŸ'ðŸ»

[Howie]

If the idle speed was low enough with the bad plugs the oil light could come on.

[ducpainter]

Don't delay getting the belts changed. You really don't want to experience a broken belt.

[SDKmann]

Definitely will, I'll likely still tow it to the shop rather than ride and give it a full run through. I would assume there is something like an OBDII scanner for these bikes right? As long as it's not electronics related I'm fairly confident in my abilities to do work myself, but obviously my ability to diagnose is lacking.

[ducpainter]

The ecu in that vintage bike is pretty primitive.

It really sounds like the bike needs basic service. Find a good shop that is familiar with Ducs.

[SDKmann]

That's too bad. Yep Im having it towed to the dealer on Friday to have it serviced (only shop around here familiar with Ducatis, gonna love this bill...) but was more curious about the diagnostics tool for future use.

Any good starting point to educate myself on these bikes that you would suggest? Would love to become more self sufficient with repairs and maintenance.

[1.21GW]

I recommend having one of these around.  Between the wonderful (if sarcastic) members here on the DMF and this manual, I have tackled some DIY stuff on my 01 900 that I didn't think I could do.

http://www.monsterparts.com/p/2VBOOK/LT+Snyder+DesmoDue+Maintenance+and+Mod+Guide.html



Also, here is a helpful site for basic DIY repair and maintenance.  With pictures:

http://www.ducatisuite.com/