2016 M8 Limited not running right

[dw8]

My father has a 16 limited that has developed a pretty substantial bog. Started to show up about a month ago around the 1500 mile mark. It's not the usual bog/deadness you get when at idle and punch it. It really shows after the machine has been ridden for say 10 miles and is warmed up. Happens when going from around 1/4 or 1/3 throttle to pinned. It spits a cloud of smoke and just has no power. It doesn't snap like my 13 does in that situation. It has fouled 2 sets of plugs. About 120-150 miles per set. We ride in Maine between 1500 and 3000 feet. The only mod is a ggb can that was added around the 600 mile mark. I don't have a lot of experience but I'm pretty mechanically savy if I can get pointed in the right direction.

Any ideas? Thanks in advance

Oh and there are no codes being thrown

 

[Frostbite]

I'm no expert but, maybe a chipped reed?

 

[007]

Three things I would do.

Replace all 4 plugs

Pull exhaust valves and make sure they are in spec

Clean clutches and replace the clutch springs

That is the first things I would do in that order

Cans can cause a bog also. If there don't work go back to the stock can and retest.

 

[kiliki]

I'm no expert but, maybe a chipped reed?

with the miles ^^^ this. stock reeds do show signs around 1500-2500 of needing to be replaced and what you have described i would bet this is the problem.
also behind the pin the flipper pivots on is the throttle safety switch you can undo the screws holding the cover in place and un plug it.

 

[sno*jet]

ive read reports on here of sticking oil pumps. i checked mine and all is good but check yours for sure. (second set of eyes on the arm while you work the throttle)