First hing to do before you try the timing is to clean or replace your spark plug,,,,, I know it souns stupid but youd be amazed how much the plug can effect the performance of your motor,,,,
2. Make sure the plug boot is on there good, it actually screws onto the coil wire,, try tightening it a bit, sometimes they loosen up a bit,,, if it does not feel snug, unscrew it and cut about 1/8 of an inch of the coil wire, then screw the boot back on till it feels good and snug,,,,
Thse two very simple things can sometimes make a big difference,,,,,
Also where you say it was sittig so long,,,, Make sure your using fresh fuel, and drop the bowl of the carb and make sure there is no gunk or water sitting in there,,,, if there is, then pull the carb and give it a good cleaning ( jets, passag ways, everything)
I suggest these first because its not too often your timing will just go out of whack,,, but if you must get the timing plugs out, use a hand held impact driver ( the kind you hit the back of with a ),, before that though, heat th case around the plug with a propane torch and try removing them with a very wide flat blade screw driver ( sometimes tapping the butt end of the scredriver with a also helps,,,,, Srry this was so long, but if any of it works let me know,,, I am happy to try to help....
2003 honda shadow 1100 spirit
94 XR600R
70 qa 50 with a 90cc motor in it
87 XR80R
82 XR500R
1972 Honda z50A mini trail,,, Finally got a stock mini
1981 CR450R
2004 chevy silverado ls ext. cab 4x4 5.3L