stuck piston ring

[Nails]

I've been chasing an engine miss for about a year, on a new-to-me bike that was rather behind on maintenance and use. In partial self defense, I had a bad coil, atrociously dirty carburetors, and I've been chasing high-altitude jetting. I also had a broken sparkplug, which was new. But I probably broke it -- when putting in a still newer plug, I found a stray plug seal down in that hole that presumably caused a fight that I lost.

The upshot is that cylinder 3 has been missing at low RPMs for a while. It ran okay at highway speed (gave 46 MPG on that tank). The miss is getting worse. With a camera, I saw fuel/oil deposits on the cylinder wall. I'll check the compression this afternoon, but I'm sure the rings are all gummed up. (I couldn't find my 12mm adapter, so now I have three freekin compression testers.)

I'm thinking of spraying carb cleaner and/or ether down there to see if I can clean things up (and burn them up).

But I also have a minor oil leak at the pan gasket. And I want to do some welding mods to the exhaust. So, I'm thinking of removing the exhaust system, anyway.

Question: is it possible to pull the heads, remove the oil pan, and then remove piston 3 (to clean it right) leaving the engine in the frame? I'm a little worried that if I keep screwing around with it a ring will break.

[cranky]

... have Ya run about 5 tanks of Seafoam thru the tank?
.. maybe a strong dose?

Might just do Ya wonders... for the entire motor!!! JM2C

[Thadbaker86voyager]

I would try putting a little sea foam directly in cylinder and letting it soak. Won’t hurt anything even if it leaks through into crankcase. Leave spark plug out and crank it to clear cylinder before putting plug back in.

[Nails]

I have a couple cans of Seafoam on the shelf. I could see filling the cylinder to soak, hoping some will wash past the rings. I can MightyVac the rest out to see if it's actually picking up anything. I'll borrow that camera again to see if this is working anything like that.

I'll probably still use lesser volumes of carb cleaner. I was thinking of ether to burn off excess carb cleaner and any accumulated/softened crud. I want to start it periodically through this process for some lubrication.

It would be swell to avoid messing with the head gasket.

[JTC1]

Back in the day we used to spray Knock'er Loose® Penetrating Solvent in the cylinders and let is sit for 24 to 48 hours. Seemed to work every time.

[Nails]

I put the piston all the way down and then shot about 100cc Seafoam in there. I left it in a couple hours, and then sucked most of it back out. It was clear and clean. Then I started the bike and did it all again, this time for about six hours. All of that drained around the rings -- I'm choosing that as a sign that it's doing something.

I also hit it with a little carb cleaner and then a little ether. But when I went to start it, the solenoid failed (see other thread). I should be able to start it on Monday.

Hopefully, it come around.

[Nails]

Success!

That starter relay finally came in, and it started and ran fine. Seafoam in the cylinder, plus a dash of carb cleaner and then ether, did the deed.