CBR600 flat spot?

[Furyos J]

Hi all, im having some trouble with a flat spot in my cbr 600 f4, it is between 5000-6000 and is most noticable under load. Ive had it in at a bike shop, and have been recomended to get
a: a dyno jet kit
b: a slip on mufflar
c: a k & n filter
and that, along with a dynotune, should all but eliminate the flat spot, i have also found refferance to this flat spot online amonst other owners of the same model bike, and the usual recomendation is the same as what i have been told.
i am getting the mufflar, air filter and jet kit all from the USA while the $$ is good (much much cheaper then getting locally) my only concern is that the dynojet kit says for USA model bike only, and mine is a jap import, no you think thereis any difference between the USA model and the Jap model (im not talking about the california models, they are different again)
thanks
J

[ducatilover]

Find your standard jet sizes and compare. My ZZR600 is NZ new and is the same spec as a US one (Not including California of course)

[Furyos J]

cool,
emailed dynojets tech support, and yep, the U.S. jet kit is what the jap or nz new model should run. sweeet.

[Furyos J]

Just to end this thread. After yoshimura rs3 slip on, dynojet stage 1 carb kit, k&n filter installed, flat spot has been eliminated. Sounds nice too. vroom vroom

[Methane_Birds]

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Just to end this thread. After yoshimura rs3 slip on, dynojet stage 1 carb kit, k&n filter installed, flat spot has been eliminated. Sounds nice too. vroom vroom

I've got Yoshimura headers arriving tomorrow hopefully. Keen on replacing the current Scorpion slip on with a Yoshi one, plus doing the filter and jets exactly as you have done. Rather than reinvent the wheel and re-do all the research you've done 6 months ago, where did you get yours and how much?
Thanks for the help,
Braeden