Low power full throttle mid rpm

[Gnasher]

Buy some seafoam.
Run the bike til there is hardly any fuel in the, tip in the seafoam into the fuel tank and run it till it stops smoking. Then top up with nice expensive fuel and take it for a blast down the country lanes, razzing it as much as you can.
When you are back at home with a grin on your face the bike should be performing much better on the way home.
If that does not work out for you it will be time to clean the carbs.

It's doubtful it will clear a blocked jet and it certainly will not sort out the contamination problem i.e. the rust or debris.  These additives are little more than detergents and will do nothing to permanently sort this kind of problem.