I wouldn't expect it to be pulse generators, You might try setting the gap at the low end of the spec just to see if it helps,
Have you played wit the choke to see if anything changes when you have it on a little?
For the sake of ease and in hopes for luck, I'd run some sea foam through the tank and carbs... beats taking them off and just might help. If the bike isn't rideable, that isn't such a good option.