Bucc,
If this engine were mine I’d tune up the ignition and clean the carb. Rebuild the carb if necessary and run it. That’s enough compression difference to likely make for a poor idle but the engine should run OK. The compression may even out with some running time.
I’m assuming when you say you pulled the inspection port that means you pulled the transfer port cover from the top cylinder. It is still possible that the rings may be partially stuck on the exhaust side and still show decent bounce on the intake side. I would not remove the exhaust cover unless necessary due to the possibility of breaking screws. No need to risk that yet. Once the engine is running and up to temp some Power Tune in it. That may help free up any partially stuck rings.
If that doesn’t work, next I’d try pulling the cylinder head and inspecting the cylinders. There could be some scoring not visible thru the intake ports. While the head is off you can deglaze the cylinders with some fine emery cloth. That may help even out the compression as well.
That’s my 0.02.
-Ben
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