Is the gas on?
How many pulls? It takes a bunch when you are trying to fill the fuel bowls after cleaning. I try to squirt a little gas into the vent lines with a syringe to pre-fill the carbs. That helps eliminate a lot of the cranking.
Is gas getting to the carbs? Pull one of the fuel lines and put the end into a bottle or container. Crank the engine over. You should get a bit of gas every time. If you don't, could be a bad pick-up line or fuel filter, bad fuel pump, or maybe a bad impulse line from the crankcase to the fuel pump. If it is getting gas, it could be a stuck needle/seat or improperly adjusted float.
If you put gas down the cylinders, mix a little oil with it to give the top end a bit of lube. I do that all the time. As long as it's got some oil in it, you will be fine. I also cheat and use starting fluid on the ones that are being a pain. If you do that, make sure the starting fluid has top end lubricant in it for the same reason.
Fuel, spark, mechanical... not much else can go wrong.
Welcome to the forum!