Piaggio sfera / zip 1 runs better cold

[padly1995]

Hello,
this is the same scooter from the previous thread, where I solved the problem with my CVT tuning. It accelerates nice and tops out at 63kph (I traded top speed for acceleration as I am using 3,25g roller weights).
Now the problem is that it goes well on quick spin, but as it starts warming up it goes less and less.
It`s stock, except for lighter roller weights, PHBG 19mm carb and airbox from lawn mower (I changed it because it goes better with it than with free flow filter) and exhaust from Chinese minareli scooter.
I am running it with #75 main jet. If I upjet or downjet it`s just worse.
Spark plug is brown.
It`s not bogging, it just looses power and top speed.
Here is the graph from speedview app.
sfera.jpg