don't worry about that head gasket.
Most mopeds have such low compression, that removing it will work similar to decking your head for higher comp.
Trust me.
Also, it is likely a fuel/air issue. make sure the pilot jet on the carb is clean. I like to run a guitar string through it.
If you are getting spark I would bet money the carb isnt all the way clean. if the pilot jet is not clear 100% it wont start.
If it ignites on starter fluid, then you know it is carb related.
good luck!