Assuming you don¡¦t have one:
Buy yourself an el cheapo digital multi meter (real cheap & invaluable). Click it on to ohms (Ă) touch the test wires together & it will read 0.0 meaning connection.
If you had a manwell for your ignition you could check with certainty.
But you can check that, for instance the ignition coil is not shorted directly to ground (except at the earth point) & that the kill switch isn¡¦t permanently on. Also check that the sparkplug cap is ok (typically 5k resistance). Check that the CDI earth wire is infact grounded.
OK without the manual here¡¦s where you start getting experimental. Basically one of the wires is earth & the others will be the lighting & ignition coils. These will be fairly low resistance, the lighting one may appear as a short. If any of the coils appear open they are faulty. This is simplistic but should find the majority of the obvious faults without writing a book.
Happy hunting.
PS
A universal jap threaded flywheel puller should set you back say $15, or thereabouts.