Z900a4 splutter

[BigZCas]

Good morning,
Suggestions please,
OK on tick over and 3000 revs +
Between 1800 and 2800 very flat, have to blip the throttle to pull off or it will die badly.
Seems to be worse when warm.
Had it set up on dyno a couple of months ago but problem still persist.
Thank you

[ZedHead]

Carbs are a lot trickier than injection to get right on a Dyno. Take it back to them

[BigZCas]

I don't think it is set up probs, more something breaking down or blocked?? ☹️

[BigZCas]

Just been out again, definitely worse as the bike gets warmer? No problem still over 3000 revs, ticks over perfect.
??

[ZedHead]

Just been out again, definitely worse as the bike gets warmer? No problem still over 3000 revs, ticks over perfect.
??

Usual suspects, if not carbs would be low voltage to the coils or something in the charge circuit breaking down. Maybe regulator or stator in that order.

[Pigford]

Yep - weak spark

[zed1015]

Try feathering the choke as you hit the flat spot to see if that cures it.
If so then it's a fueling gap coming off the pilots ( try lifting the needles a notch ) or partially blocked pilot circuit .
Stock air box or individual filters ?
If individual filters you may need air corrector jets fitting.
Bogging can also be the result of bottom end over richness and the revving can clear the excess fuel and plug fluffing so if the above doesn't work or makes it worse then try the bike with the air box or pods removed .
If you have pods and they are the cheap Emgo type then they could be the problem as they are actually more restrictive than the stock airbox.

[BigZCas]

Standard airbox.
It must be something that the Dyno did not pick up??
Thanks for suggestions, I'll try them one by one