Is that 2 year old gas in the tank? If so you need to dispose of it, it's not good for anything but maybe a bonfire.
Goldarrow has it right, you know it turns over, which is good, but a bike that has been sitting for 2 years outdoors (even with a tarp) is going to need at the very least (1) an oil change (2) the tank cleaned. If the carbs had gas in them when it was parked then you will almost certainly need to clean out the carbs as well.
Personally I would order the carb gasket kit for your bike, take off the carbs and give them a good cleaning.
2 years ago I revived a '77 550K that had been sitting (with gas in it!) for 28 years. The only significant work I had to do was cleaning the inside of the tank and the carbs.
A couple of weekends of work should get it to the point where it will start. If you have to jump the solenoid my guess is that you will need to clean the contacts on the starter button.
