What the #%$^ is in my crankcase? (w/photos)

As part of a clutch overhaul project http://www.xjbikes.com/Forums/viewtopic/t=31799.html that required dropping the sump cover, I found this: http://s1136.photobucket.com/albums/n48 ... %20sludge/

The sludge is a really thick, molasses-like consistency. It seems to be contained to the sump cover and pump aree. The rest of the case is clean.

Then there's this big hunk of plastic??

This bike sat for several years. I got it running and it ran really good, but the clutch was seized and that led to this discovery. What now?

 

The "sludge" is what you get when you succeed in mixing oil with WATER. This happens when you get an oil/water mix hot. You must not have changed the oil immediately, and run the motor with water still in the crankcase (or a PO did.)

Usually, big hunks of plastic found in the sump come from the "primary" chain guide disintegrating. While that is always a possibility, that doesn't look like a piece of chain guide. I have no fogggy idea what it is.

Let's hope somebody else recognizes it. I "imbedded" a couple of your pics for you:






So c'mon big bike owners, what is this a hunk of anyway?

 

Thanks bigfitz52 for embedding the photos. I couldn't figure out how to do that.

I should have included something for scale in my photos, but the piece of plastic is about the size of a quarter.

 

When you go to your Photobucket gallery, simply click on the "IMG" link for the photo, it now automatically copies it and all you need to is paste it in.

I can't for the life of me figure out what that could be other than a hunk of the primary chain guide.

Your sludge is for sure an oil/water mix.

 

wow, I have no idea what that is. It looks like a piece of hot injected plastic. Almost like the cush drive on a chain driven bike.

 

Anyone have an idea what this UFO is?

It may not even matter at this point. I suppose the fix would mean breaking the case down. At which point, I'll know what it is.

 

Sorry Thomas TX thats part of the primary chain guide

 

I thought the 650's and 750's were gear driven - i.e. no primary chain... Not the case? Or does "primary chain" mean something different on these bikes?

 

It means something different. Kinda like the "choke."

They CALL it the "primary" chain; it's really only the "jackshaft" chain, as all it does is connect the jackshaft (starter clutch on one end, alternator on the other) to the crankshaft. On the XJ550/600s, it actually drives the transmission, and so in those bikes, it's a "true" primary chain. Thankfully, in those bikes it's also hydraulically tensioned with a slipper foot not prone to disintegration.

 

it's got to be a primary chain guide the only other thing in there is the cam chain guide and they look nothing like that

 

Here is a pic of one for sale on ebay. http://bit.ly/m2x8oM

 

Ya. Chain guide. Here's a piece of my broken one, and the replacement about to go in (courtesy chacal (Len)).

 

Oh yeah - That's what it is! I guess it's better that I found out now, not after I put some shiny new clutch parts in it and rode it for a while.

It looks like my parts bike and my primary bike night be trading places.

Thanks to all for the help.