chasing geese again.
firstly...get an ngk plug.
then start of with the basics and find out WHAT THE PROBLEM IS systematically.
so, it has spark. we think so, we can see it. doesnt really mean doodly squat
now...is it the timing, or is it fuel...how to tell?
by removing the carb, pouring a few cc of fuel down the intake, and giving it a go.
if it starts, you have determined that the problem is a fuel issue, so look inside the carb etc.
if it does not start, well...then it must be an ignition or compression issue.
having figured out which way to go, you can then search for help on whatever area you KNOW is being a problem
of course, this is assuming everything else is correctly setup, and it isnt clutch slip or something similarly silly.
dont assume that if its new that its right...
theres posts on here of reverse magnetised magnetos, and also backwards wired cdi's...
the missing key behind the magnet is pretty common, and the occasional bad earth to a head pops up... always check the plug on the head, the bit it bolts to and earths through
crankcase can be deceiving...
carbs come with badly adjusted floats, blocked jets, black bits of unknown stuff in the bowl, etc etc etc...
erm...