Oil leaking into exhaust…worn turbo?

Hello, I just acquired a 1982 Yamaha XJ650LJ Turbo SECA. It did sit for quite a long time, more than 2 decades in a garage under a tarp.

Well now it seems to pool oil in the exhaust when running for more than a couple minutes. Before I started the bike I pulled apart the exhaust, emptied the oil that was pooled in it, inspected and cleaned the turbo oil supply line check valve, put it all back together and fired it up. I am now suspecting it is in fact the turbo itself that has let go. Some of the oil that leaks out the exhaust also contains a greyish looking slop in it, which appears to be from oil that has passed through the turbo. The only thing I have not inspected is the return line for the oil, but I suspect issues with the return line would only manifest when the bike isn’t running? Not too sure. Any thoughts are appreciated.

 

Most times with these bikes there is pooling of oil in the turbo when the bike sits.
I suspect this might still be an issue for you but not disagreeing that you may have excessive oil leaking past the turbo seals.
The age of this bike might be reason enough to consider a turbo rebuild.

Most suspect the check valve in the turbo supply line and this is a logical assumption.
I found mine working correctly, however I found excessive oil leaking past the scavenge pump.
I believe the aluminum surfaces in this pump become worn, the easiest solution is to install another check valve in the scavenge line.
There is a rubber seal on the pump if faulty might prevent the pump from sucking the oil from the turbo.

Have a look at page 6&7 in my turbo restoration. It's easy enough to disconnect the lines and see how much is leaking past the inlet and outlet lines.
Page 7 shows the seals on the pump.
https://xjbikes.com/forums/threads/simmys-naked-turbo-project.110254/page-6
https://xjbikes.com/forums/threads/simmys-naked-turbo-project.110254/page-7

check valve installation
https://xjbikes.com/forums/threads/simmys-naked-turbo-project.110254/page-10

Let's see some pics, what is the condition of this bike?

 

I have a lot of the plastics off as well as the exhaust removed, all the way up to the turbo. For the age I’d say the bike is in decent shape. Not mint by any means.

I think the next step will actually be removing the turbo itself. I’m curious about the issue you mentioned about the scavenging line. You think it’s failing to retrieve oil from the turbo, and it’s just pooling up inside? Leaking everywhere?

 

I mentioned it as a possibility but I don't think that is your issue.
I suggest letting it sit with both turbo feed and scavenge lines draining into separate containers, easy to do if you're removing the turbo anyway.
This will tell you if any oil is pooling while sitting and which line is the culprit.

I had my turbo unit professionally rebuilt.
It wasn't too expensive and just decarboning it is a good idea.
The seals are like piston rings, they are designed to leak a little bit for some lubrication.
I'm not dismissing this as your issue.

What is the mileage of your bike? It does look pretty good.

 

Thank you for the suggestion! I will do that. It has 21,090 miles. I’m in the process of removing this turbo, and I removed the exhaust pipe on the drum brake side, and…this photo is what I found. Not good.

 

Upon further inspection after turbo removal, it would seem the turbine and compressor wheels are both in tact, and do rotate. All the chunks of rusty metal appear to have come from the wastegate, which appears to be in questionable condition. The metal around it is all rusted and flaking inside. My next question is, would xj4ever take this unit as a core? I know it’s supposed to be rebuild able.

 

Definitely needs dismantling.
I suspect it just needs cleaning and new seals.
Your wastegate looks completely plugged, must have been mice nesting in there.
Was this bike ridden like this?

 

It was one time, yes. I was told after that one ride is when it started leaking oil bad. Before that ride, the previous owner had a long list of work done to it just to get it running, it had sat for 20 years. I started it yesterday before I suspected the wastegate was completely clogged with rust, didn’t ride it anywhere. Just let it idle. After discovering all this I’d be inclined to check air plenum to the carbs but, I’m not really noticing anything in the intake tubes that connect to the turbo.

 

I am currently making arrangements to replace the worn turbo unit. I am curious about the wastegate actuator. Does anybody know of a good way to test the functionality of it? I don’t want to reuse it if it’s bad.

 

If you have a pressure regulator you can blow 7-10 psi into it to make sure it strokes

 

Update:

Good news! Rebuilt turbo installed and bike is running! I may need to investigate a little smoke in the exhaust but I’ll wait and see if getting out for a good long ride eliminates the smoke. I have a theory it is residual oil in the exhaust getting burnt off. it could also be the motor itself? I may also have an issue with either the boost pressure gauge (no boost showing even at 5k rpm) or the reed valves in the intake…plenum? I can’t remember what it’s called.

The bike seems to run well, idles smooth and throttle response is decent. I changed the oil and followed the procedure for supplying oil to the turbo before the motor started to ensure it wasn’t running dry for any length of time. Time to insure, register, and plate!

 

In my experience the digital boost gauge goes full stop as soon as it sees boost.
It is useless as your seat of the pants will tell you it's under boost anyway.

You are doubting the integrity of the reed valve, does this mean you are not developing any boost pressure?
These things don't develop any boost under 5k

 

I am a little concerned it’s not developing boost yes. I won’t really know for certain until I have the opportunity to really open it wide and see how it feels though. So you mentioned the boost gauge really behaves in more of an on/off fashion?

 

Wanted to post an update here, with the bike fully legal I've had the chance to take it for a few rides. It runs great!

I was initially concerned about it not developing any boost. But after really riding it I now see I was wrong. It does develop boost, and the power is wild. Never experienced anything like that. Major shoutout to Len at XJ4Ever. Without his help getting me the rebuilt turbo, this bike may not be running right now. Thanks for your input as well.