Crud in the Oil

[Carveacre]

1981 XS650SH stored in a damp shed for 28 years. My previous thread was Got it Back. I changed the oil and filters, and scraped some crud that looks like broken pieces of black plastic off the small filter. Nothing on the sump filter. What could this crud be? With the new oil and filters in, I plan on stroking the engine 10 strokes with the kick starter every day for the week or so I am derusting the gas tank and cleaning the carburetors. Will it be safe to try starting the engine? It strokes freely with no noise with the spark plugs out. Thanks for your concern and your good advice. Carveacre in CA

 

[zrx1100]

$10 its the cam chain guide deteriorating

 

[zrx1100]

an opportunity to open up the top end and bump up the performance. that is what I ended up doing when I found plastic peices of the guide during an oil change a year ago: https://www.xs650.com/threads/700cc-kit-with-a-shell-1-cam-in-a-78xs650e.65405/

 

[Its been a long time]

$10 its the cam chain guide deteriorating

Not a lot of doubt about it, I suspect.

 

[zrx1100]

one question is why you are finding these pieces in the small filter. usually the sump filter should catch these. Is the mesh on the sump filter intact?

 

[nj1639]

No aluminum bits? I'd start it.
I'll have to add that my wife is part Sicilian so consider that in my judgement......

 

[Carveacre]

No, there is a 3/4 inch square hole in the mesh. I have replaced the sump filter

 

[zrx1100]

No, there is a 3/4 inch square hole in the mesh. I have replaced the sump filterView attachment 263750

Ok. That explains how the pieces got to the small filter.

 

[zrx1100]

Here on the right are the bits that I found at the sump filter. When I opened up the motor, the lining was completely detached from the guide (the parts in the picture) and the cam chain started to carve into the aluminum body of the front guide. These is a lot of discussion about this issue on the forum as the guide is a common failure in these bikes with age.

 

[jetmechmarty]

This is the sound you’ll hear if all of the plastic comes off of the tensioner foot. That and you’ll about run out of adjustment. Until then, run it.

 

[Carveacre]

I have 3 possibles, and I don’t know which to get. EBay, Mikes XS, or XS650 direct.

Ok. That explains how the pieces got to the small filter.

 

[zrx1100]

This is the sound you’ll hear if all of the plastic comes off of the tensioner foot. That and you’ll about run out of adjustment. Until then, run it.

I would not run it. Just imagine larger pieces getting into the chain at the crank sprocket. I do confirm this noise as a sign that something was wrong and I did run around with it for a couple of months

 

[Its been a long time]

This is the sound you’ll hear if all of the plastic comes off of the tensioner foot. That and you’ll about run out of adjustment. Until then, run it.

I assume it's an engine out job to replace this?

 

[Jim]

That Ebay guide isn't for an XS650. It won't fit.

 

[zrx1100]

I assume it's an engine out job to replace this?

Yes. Jim has a nice write up on how to put it all together

 

[Melnic]

My 78 sounded fine but I could tell my cam chain was stretched cause I was at the end of my timing adjustment on the points. Pulled it open to change cam chain and look at the front guide and change it while I was in there only to find the plastic totally de laminated. I could not hear anything wrong at the time.
before pulling it apart I had a few little plastic bits in my fuel filter and like yours (and many of us) the sump filter was blow in.

https://www.xs650.com/threads/1978-xs650-special-project.65053/page-13

 

[jetmechmarty]

I assume it's an engine out job to replace this?

Yes, the cylinder head must come off.

 

[jetmechmarty]

I would not run it. Just imagine larger pieces getting into the chain at the crank sprocket. I do confirm this noise as a sign that something was wrong and I did run around with it for a couple of months

Mine shed a lot of plastic off the edges. The chain was still running on plastic. The engine in my video shed the plastic completely.

 

[zrx1100]

You can even avoid breaking the cam chain by sliding off cam shaft bearings for a minimally invasive fix. That said, why not replace the cam chain while you all the way in there anyway. Also not sure how the base gasket is going to continue to seal with the pressure taken off and retightened.

Yes, the cylinder head must come off.