Whats up with the clutch? When I pull the clutch lever it travels all the way down with no pressure. Did sitting in the gas/oil mixture trash the clutch, or do I have to do something to get oil into the clutch chamber?
Start with the simple things first...it's not likely a problem with the clutch itself, assuming it was working previously.
1. Check the cable, especially both ends. If there are any broken or frayed wires, then you will need to replace the clutch cable.
2. If the cable is fine, then adjust the "free-play" on both the top and bottom, until you have only approx 1/8" free-play at the lever.
3. Next would be to check the clutch release "ramp" assembly, which lives under the countershaft sprocket cover. Remove the cover, and dismantle, clean and relube the release ramp. While the cover is off, remover the "pushrod" and check it for damage, bends, etc. (This should be done every year or so anyway, to clean off the accumulated mung from chainlube and road grit).
I'll bet your problem is cable related, but let us know what you find out doing the above.