I checked my favorite town database for any appropriate towns in Eastern Europe starting with "Yob…" or "Job…" and came up blank. I also searched for any towns that ended in "…neks" or "…necks" and also had no hits. I think you should assume that the town was being written down phonetically on the draft card by an American who was dealing with an immigrant who spoke little English.
Based on that, I believe the town may be Vabalninkas, Lithuania. It is a very small town located at 55°58' N 24°45' E, and it is 91 miles NNW of Vilnius (formerly Vilna). Prior to WWI, the town was known as "Vobol'niki" in Russian.
The giveaway is that the Yiddish name for the town was "Vabolnik" or "Vobolnik", which kind of sounds like Yobolneks -- and it's even more of a match if what you thought was a "Y" at the start of the word on your draft card was actually a "V" with poor handwriting.
The town is being researched by many people at JewishGen:
If you join the JewishGen Family Finder (JGFF) there, you can connect with them and see if you can find a match with another researcher.
It looks like the remains of the Jewish cemetery have been photographed and transcribed and are included in the JewishGen Online Worldwide Burial Registry (JOWBR), if you want to search through them.