Spark Plug kinda stuck?

[Moki of Rancho]

Hey all. Finally putting the bike back together after many, many weeks of insanity... went to torque down my spark plugs, but it seems that plug no. 2 doesn't want to tighten all the way down. It threads about halfway, then starts putting up a lot of resistance. Having been a professional broken-bolt-remover in the Army, I decided not to force the issue. Anyway, I pulled the plug out and the threads on it look fine. I swapped it with the no. 1 plug anyway, just to be sure, and ran into the same problem when I threaded it about halfway down. Hard to see down in the plug hole, but I felt around the internal threads with a finger and they don't seem to be stripped. Is there anything mechanical that might stop it at that point? Any and all suggestions appreciated.

[Steve]

Even if you can't see anything, the threads might be crossed or have a piece of dirt jammed in. Try spraying some cleaner or lube in there, followed by swabbing with a bristle brush. If that does not clear it, get a thread chaser at the auto parts store, lube it up and use it carefully.

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