78kz220a ignition timing help PLEASE!!

so im and going to buy a 78 kz 200a from a friend. it will start sometimes but either has a really high rev, and you can give it gas and it will accelerate, or it will have a really low idel and when you try to give it gas it dies, also, when at a high rev and you go into 1st it will go to a low idel and not take off and die. i have changed the plug pulled apart the carb and soaked and cleaned it, fuses are good i have compression and spark and it is a hard start but starts after like 10 kicks. and then will die out from tinkering and then is a pain in the ass. so my friend has been playing with the carb as well as the timing points. i was wondering if anyone could give me tips on where to start with the timing as well as with the carb, I live in colorful colorado so i am over 5200 feet. i was wonderingabout jets and needles but can really find any expert advise. and help would be amazing!!! i cant wait to get onthe road fiiinally!!!! thank you in advance. Dodson

Hello, Dodson, and WELCOME to KZrider!

Would start by checking valve clearances, and adjusting them if necessary, to specs.

Good Fortune!