Piston circlip took a walk! GS1100E, ever seen? No visible damage to cylinder

[oldGSfan]

I decided to yank the motor out of my parts bike '82 GS1100E, and see if I could figure out the loud whining noise it was making. Before pulling I checked cam chain, ignition area, clutch and starter clutch/stator areas to see if I could see anything there, but it all looked fine. Out came the motor and off came the top end.

I found this on the #1 piston outside circlip. The undamaged circlip was in there, in the correct slot. I can't find any damage to the cylinder wall or anywhere else. The whole top end looks quite good apart from this, no galled threads or score marks on journals etc.

Judging on the overall lack of evidence of any damages to screw and bolt heads and general condition, it could be a motor that never was apart, but who knows, I have no history. It would seem to be an assembly error that isn't likely at the factory though (my guessing). No idea if this caused the whining as it's off and isn't going back together.

I'll be selling all or part of the complete top end (cheap!), am wondering what else I can look for to ascertain any damage it might have caused, but I'm not going to dive into the bottom end. I didn't find any metal shards when I first got the bike and changed the oil and filter.

 

[zed1015]

Seen similar to that a few times .
The only apparent cause being a weakened/loose circlip that moves around and works the groove larger .
Not suprising given the jiggling it gets during the millions of strokes the piston has gone through.

 

[Rob S.]

What color, and condition is the fuel tank in?

 

[oldGSfan]

I'll PM you, I do recall you asking about it.

 

[oldGSfan]

Thanks. I have only taken apart a few engines, some I even got running again!

Seen similar to that a few times .
The only apparent cause being a weakened/loose circlip that moves around and works the groove larger .
Not suprising given the jiggling it gets during the millions of strokes the piston has gone through.