Can this Cylinder be salvaged!!!

[KTM640]

I've got CAD bad. Picked up another project even before I finished my last one.
The pics are the piston and cylinder from an 064 that I picked up. The walls of the cylinder look smooth, but the top of the cylinder is all pitted with what looks like carbon. The top of the piston looks pitted, with a ridge around the edge of the piston. View attachment 69192

View attachment 69193

I haven't seen anything like this before and wanted to get input from yall on what you thought might have caused this and if any of it is salvageable ..

Thanks

Jon

 

[blsnelling]

I can only guess on this one. Could it be from detonation, pinging? I've never seen anything like it.

 

[Bowtie]

Its toast, I'll give ya 10 bucks plus shipping.

 

[04ultra]

Check big end rod bearing carefully............I had a 200T that did that and the crank was junk too......Small end bearing was completely apart..

 

[PB]

Bearing break up? How do the crank bearings look?

 

[blsnelling]

It almost looks like a rather large foreign object lived in there for a while. But if that were the case, it would have caught in a port long before now. Plus your walls don't appear to be damaged. If it were from debris from a wasted bottom end bearing, it would have to have come up through a transfer. Again, he doesn't have any cylinder wall damage.

 

[Lakeside53]

I'm betting a main bearing came part... Check them carefully...

 

[Bowtie]

The pics are hard to see anything, but that isnt just carbon flaking? Maybe not, I might be way off. Better pics would help.

 

[PB]

What does the piston skirt look like?

 

[04ultra]

This 200T was from bad gas......

 

[blsnelling]

Take a look at this crop. Does this appear to be a build up, rather than a beat up aluminum surface? Or is the surface of the piston eroded away up to the edge where it couldn't hit it? What in the world could cause a buildup like this? Take the piston crown to a wire wheel and see if it comes off. Take care not to damage the piston edges.

 

[04ultra]

It almost looks like a rather large foreign object lived in there for a while. But if that were the case, it would have caught in a port long before now. Plus your walls don't appear to be damaged. If it were from debris from a wasted bottom end bearing, it would have to have come up through a transfer. Again, he doesn't have any cylinder wall damage.

On mine the big end bearing looked good but failed the pull test....

 

[Bowtie]

Good pic Brad. That looks worse than what I thought. What yall think?

 

[04ultra]

Good pic Brad. That looks worse than what I thought. What yall think?

TOAST................

 

[blsnelling]

On mine the big end bearing looked good but failed the pull test....

Can you explain how this failure and resulting damage occured?

 

[04ultra]

Can you explain how this failure and resulting damage occured?

Mine was from detonation due to bad gas........Water maybe in gas.........Have Stihl#1 explain it to ya......Or Andy...





THALL sent all my pictures down to Stihl.......

 

[KTM640]

More pics of piston, and transfer ports

When I got this it was in pieces and there was not a wrist pin bearing. The lower rod bearing looks to have all the rollers. I did the pull test and there is no play up and down. Side to side, there is a little rocking.
View attachment 69200

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View attachment 69202

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View attachment 69204

Here are more pics on the side of the piston, transfer ports and inside of the bearing on the clutch side of the case.

Jon

 

[PB]

Refer to page 72.

 

[04ultra]

When I got this it was in pieces and there was not a wrist pin bearing. The lower rod bearing looks to have all the rollers. I did the pull test and there is no play up and down. Side to side, there is a little rocking.
View attachment 69200

View attachment 69201

View attachment 69202

View attachment 69203

View attachment 69204

Here are more pics on the side of the piston, transfer ports and inside of the bearing on the clutch side of the case.

Jon

Piston damage........Looks like pin bearing .......

 

[KTM640]

Here is a picture of the bottom of the crank. Something definitely found it's way in there..

View attachment 69206

Thanks for all the feedback.

Jon