FZS600 - No power, won't go faster than 50, engine not smooth

[Torque]

Thanks guys for help.

Mileage?
Service history / recent work?

Mileage 40k+, service history unknown from previous 10k.

You say you've replaced parts - what were they (ie, is it possible you've disturbed something during the work you've done?)?

Just suspension and brake system. Shouldn't affect.

You say you pulled the plug leads off - the cylinder you disconnected must have been firing properly (hence why it ran even worse after; if it were faulty, pulling that lead off would make no difference). Have you tried the same with the remaining leads (or, indeed, have you one downpipe cooler than the rest?)?

I've tried all cylinders and all of them works fine (because it works much worse after pulling plug leads off)

Have you had the tank up/off?
Kinked fuel line maybe, and is the fuel tap switched fully on?

No I hadn't last time, however I will double check it.

Assuming guys you point fuel issues, then I will focus on it. It's already dark, but hopefully tomorrow morning if it's not raining I will be able to do something.
Thanks you are insane