carb inlet rubbers

[king1]

Hi
I am after some help
My bike is running on kangaroo juice
I have cleaned out tank, cleaned carbs, oil and filter change.

The symptoms and motorway cruising speed it is stuttering, at fast acceleration there is no power and it even slows down.

I have been told it could be my carb rubbers that are leaking as they are cracked,

Could this be the problem, I was going to try sealing them and wrapping tape round them, alternatively new ones are £70.
I have been looking at other topics on the forum but still need help

Any advice

Thanks
Kelvin