Have you tried a 280-290 main? Cleaned carbs really well? I've seen electrical components cause a break up rpm as well. Sent from my SM-S820L using Tapatalk
What brand of cylinders? What did the rings look like? If you bought the cheap niche / eBay cylinder kit your mechanic probably should've chamfered the edges of port Windows. They are sharp af. Sent from my SM-S820L using Tapatalk
Unplug it, and throw it. Tors delete can be had for $50 give, or take, they clear up the clutter, and look clean af. Sent from my SM-S820L using Tapatalk