Stuck rings...

[tkent02]

Old 850 pistons, been sitting in the cylinders forever I guess. Both rings are really stuck on one of them. Oil rings came out easily enough, compression rings are both stuck tight. Ring gap is too small to get a tool into. Been soaking the pistons in Simple Green, tried carb dip, even tried boiling in lemon juice ( got them really clean but the rings are still stuck)

Any other ideas?

[chef1366]

Shoot, I was going to say soak in Berrymans for a couple of days but you tried that. Heat maybe?

[Nessism]

Marvel Mistery Oil works well for things like that. Worked with a GM engineer and they recommended the stuff to free up stuck rings in some of their engines - similar to GM Top Engine Treatment, only cheaper.

[Big T]

Seafoam says right on the side of the can that it will do the job. I have not tried it, but you wouldn't be any worse off.

I think heat would be good, put them in the oven at about 350 for 10-15 minutes. Make sure your wife is gone for a few hours

[tkent02]

She's been gone a few days, but I can cook in the garage now anyway.
Think boiling in Marvel Mystery Oil will be my next attempt.

[chef1366]

Gee, I wonder what you could be cooking in the garage?? :shock: ;-)

[catbed]

if you have the engine off the bike, you can put kerosene or similar in the cylinder and light it. the heat will expand the walls but the kerosene with keep the piston cool and it will not expand. just have a fire extinguisher handy just in case.

[tkent02]

My mistake, the pistons are out of the cylinders, just the rings are stuck in the grooves.
Got one end of the lower ring loose...
Don't want to damage the piston or it's grooves.

[catbed]

oops, suggested berrymans without reading your original post again.

if your take a razor and slide it around the top and bottom of the ring, it might free it up a little bit.

[chef1366]

Wedge something in the ring gap, tap and break the ring out in pieces.

[TheCafeKid]

I had a similar problem rebuilding my rear master. The circlip in the botom of the master cylinder was rusted in place. I tried everything, PB, heat, trying to scrape the rust out. Wouldnt budge. Ended up wedging a small cold chisel in there just as Chef suggested, and tapping it a bit with a hammer and it came out in peices. No damage to the MC. Cold chisel might work as generally they are fairly dull.