Hello i have problems with 2 of my bikes.
Both Cags
#1 wont start, Brand new Carb (worked the first few times), New throttle cable (because it wouldnt fling back before freely)
I have checked that there isnt a leak in the cylinder, the spark plug is sparking and getting slightly wet (you can feel oil) and the carb should be working as it is new...
I did open the engine (took off the cylinder) and it was left like that for a few days open because somebody broke a new piston ring

(not me) for a big bore kit. But i ended up putting it all back together stock. And im pretty sure there is no air leak.
I cant wrap my head around what can possibly be wrong with this?
Could the spark plug possibly be the problem even though i do see it sparking? Should i buy a NGK one?
Is there any other possible problems?
I am noob, so please be patient with me.
#2 Starts, but when i throttle it stalls.
Carb has been thoroughly cleaned, Spark plugs checked to be sparking, no leaking. Could it just be the spark plug slowly dying and could i need just some new NGK Ones?
Thanks for any answers, im new to all this.
THANK YOU!