CG 125 Engine running like crap after rebuild

Hey all, I recently did a full rebuild of a CG 125 engine I had as the crankcases were damaged, the engine was running before the rebuild. I just cant get it to run well! Although I am OK with engine rebuilds I am not so good with carbs, and wondered if someone with more skills than me could help me out?

https://www.youtube.com/watch?v=-uJOmDeOrGw

Here is a video of it running on full choke (Black smoke out exhaust means too rich?) and you can see the bike just cuts out when the choke is off. Also I try revving it up with full choke and you can see how that works out.

Many thanks!

PS please note this is in an XL 125 and has a bigger bore exhaust than a CG 125...

Carb needs a damn good clean out, pilot system is probably blocked.
You will need slightly larger main jet to compensate for larger diameter exhaust but low end needs fixing first.