.Mine doesn't change much when the #1 plug is pulled. A worn cam, I suspect, as new carbs didn't change the symptom and compression is A+.
When pulling a plug wire to a cylinder does not affect the running that is a symptom of a problem. You always start with the basics, compression, ignition and carbureation with sound diagnostic procedures and test equipment along with the knowledge to apply it to a given problem.
Pushing the 300k miles bike has, you start looking at other problem areas in high mileage units for a weak cylinder such as a weak valve spring, worn guide, worn rocker or adjuster, or a lash adjuster that is partially collapsed from a possible lower than normal oil pressure with that mileage, all more likely than a worn lobe which can be confirmed very easily with a micrometer or dial indicator and a visual inspection. All of these items will probably show a comparable static compression test result, only with the engine up to speed does it become apparent.
And all the above can be checked easily with the right tools, knowledge and experience on how to use them.
If you are ever out my way drop in and we should be able to figure out the reason for bikes discomfort.