Alternating idle?

[fstnd]

It sure sounds lean, I didn't tune it. This was the first time I started this engine in this baja with this carb.

I've ran lean before, but I never had an unstable idle like this, what could be the cause(s) of it?
Could it be due to old fuel or, please not, a somewhat clogged carburetor?

 

[Beer_Goggles_RC]

Definitely does sound lean. Maybe an air leak?

 

[fstnd]

The engine wasn't like this last time when it was running, I wouldn't think so. Thanks