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I would like for you to run a leak down test, much different from a compression test as if you have a leak not shown on compression reading it could cause a lean running condition on that cylinder, common lean issue.
You stated carb was vatted, I assume you installed a full new rebuild kit?
If the engine is factory spec and you are running an correct application carb then you should not be needing to change any jets or anything else.
Next thought would be an actual problem with the carb requiring replacement of the carb, but you should also check spark with a spark tester watching as it jumps the gap and checking if weak because it may be firing but not correctly (and chances are it is not spark related as you stated it is running lean not rich) so my thoughts will be nothing related to spark.
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