Strange engine running problem

[Hillbilly Bike]

My bike normally runs very well from cold start ,through warm up and fully warmed up. It' s got a jet kit, Uni filters,different muffler and pulls strong from low to high speed...
But lately there's a glitch...The bike starts as usual, ride off and all is normal for a few miles and then the engine devolops a noticable bog off idle. But once past the flat spot all is normal and it idles normally. Full power is great although I don't like to flog the engine till it's fully warmed up. After a few minutes the flat spot disappears completely and runs with no issues....engaging the choke has no effect on the problem. The tank is clean, new petcock, fuel filter , newer quality fuel hoses..and it has the Mikuni vacuum pump conversion . There is a few pops out the exhaust during the problem like it's it's ignition related but no sneezing through the pod filters like a leanout issue..The plugs look good ....
Any ideas?

[6]

When is the last time you cleaned the carbs?

I know that's basic math.... But they can gum up little by little.

You could have a slide starting to stick, thus the bog of idle that goes away once they have started moving free.

[squirrelman]

try tuning the idle mixture screws following the fsm idle drop procedure. make sure the choke isn't sticking partially on (no slack in cable).

[Hillbilly Bike]

Thanks for the info....The carbs were cleaned 500 miles ago ...I will go through the ile drop procedure