Would there be any negative ramifications to shooting my Yugo with the gas shut off?

Not really other than having to use it as a bolt action.

Not sure how it works on the Yugo, but my friend had an M1A that we were monkeying around with, turned off the gas acidently, didn't have a manual. Well we get to the range, he get's one shot off and then the thing locks up completely, couldn't get that bolt open w/out raming the bolt handle against the top of the bench to get the empty shell casing out.

As I said this may not be the case with the Yugo, but was a real pain in the ass with the M1A until someone pointed out that the gas was turned off. Both of us felt like real idiots!  

I couldn't help myself, I had to try my Yugo as a single shot.. I put the gas port switch to "grenade" mode and let fly with one round of the Wolf.  Nothing exploded, I'm still typing with 10 fingers and no (new) scars.  The kick was greater, but my oh-so-scientific one round test seemed a little more accurate.  The only problem I experienced was that the bolt was a REAL BITCH to cycle.  I continued to shoot it afterward, putting maybe another 200 rounds thru. Fair warning though, I may have just gotten lucky, and at my next outing with the gun the damn safety lever snapped off and nicked my nose after about 30 rounds. (more on that in another topic..)  I've no idea if the two were related, or if firing the yugo single really is remotely safe, but my curiosity is satisfied :)