GS550L Motor Issues
 

Hey everyone, I'm pretty new to motorcycle tinkering and just bought my first bike, a 1980 Suzuki GS550L. (200 dollars with a clean title and relatively low miles!!!) The bike has sat a while (10-15 years) and doesn't currently run. After getting the carbs off, I looked inside the motor and it's a little crusty. I dripped mystery oil down the cylinders and blew them out with compressed air. I plan on doing a compression test tomorrow. The bike does roll over freely and FEELS like it has good compression. Aside from the mystery oil, is there anything else I can do to clean up inside the engine?
Also, other than the routine (carb cleaning, oil change, fresh gas, plugs, air filter ect.) Is there anything else that I should do before trying to fire this baby up? Thanks in advance!