KZ400 will start but will not run

Hi, you guys are very helpful! This forum has a great community! All the problems I had, I put it on here and are solved
Anyways, so I am starting up my '74 KZ400. It will start but, 2 or 3 seconds later the engine turns of. Or sometimes it runs for 10 seconds, but when I ease on the throttle, it shuts off. What can the problem be?

Hi Kyan,
Has this bike ever run for you before? How much maintenance have you done so far? How clean is the fuel tank? My first guess is dirty carbs. Some more background would help.
Regards and Welcome to KZR!
Bill

When I first got the bike, which was 2 weeks ago, it was starting and running. The previous owner has changed the oil for me. But I did not turn it on or start the bike for 2 weeks just because the battery needed to be charged and I barely got a charger. I am not sure how clean the fuel tank is. I have not checked the carbs either.

kyan44 wrote: ... I am not sure how clean the fuel tank is. I have not checked the carbs either.

That's where I'd start. If you drain the carb floats and find the dirt I bet you will, a thorough cleaning is what's required.
There are a couple of good primers in the Tech Tips section of this site. You could start here:
www.kzrider.com/articles/technical-tips/123-carb-cleaning-101
Bill

Kyan, not sure what part of the world you are from but in much of the US it is (somewhat) cooler now than traditional riding season is. KZ400s have a well-earned reputation for not liking the cold very much. Mine is dialed in pretty good but even when it is nice and warm outside I need to let it idle a while (a minute or two) before I can touch the throttle to give it any fuel otherwise it will cough and sputter and die. When it is colder outside I have to let it run even longer before it will take any throttle. So I think at least that part of your question I can answer with "That's pretty much normal".