Motorcycle Repair: YZF600R revs quickly with no acceleration, poor college kid, clutch lever

Question
I have a 2000 Yamaha YZF600R.  I recently had the carburetors replaced and changed the oil because the old carbs caused gas to leak into it (plus it needed a change anyway).  I have not had the bike long so I don't know much about it's history.  I live in Kentucky and it's starting to get fairly cool (60's).  My problem is that when I try to accelerate quickly by giving the bike a lot of throttle, the RPMs jump up quickly but the bike doesn't accelerate.  It seems to only do this when the throttle is opened up a lot. Drives fine with normal operating conditions.  The carbs were replaced with new carbs.  I had a garage do the work for me.  I'm unsure if they cleaned the carbs before putting them in (would assume they didn't put really dirty ones in).  I tried putting the cheapest motorcycle oil in it($6 something per liter..i'm a poor college kid).  The bike has 12,400 miles on it.  Any advice?

Answer
It sounds like the clutch is slipping. Did it do this before you changed the oil?

You may have burned out the clutch if you ran it with gas in the crank case.

Check the clutch cable for the right slack. You need 1-2mm of slack at the clutch lever. If that checks out, you may need a new clutch.