Gas gas ec300 not hitting powerband

[candybuddy]

Hi my gas gas ec 300 no longer hits powerband when it has warmed up, it still starts first kick and idles fine has full power when it is cold but as soon as it is warm it does not hit powerband. There is still lots of low end power but its like theres a rev limiter before the powerband. I've done a bit of research and people say it could be carb related.

Can anyone help would be much appreciated.