Hi Gearhead222,
It is impossible to give exact information without knowing exactly which version of the motor is installed in the bikes.
As an example there were at least 5 different heads used on the NE motors, 2 different ignition sytems, 5 versions of the 22 MM carburetor, one 26 MM version, steel head gaskets, copper head gaskets, 4 different intake spacers, 3 different camshaft settings, two types of lifters, 2 different camshaft grinds, 2 different muffler inserts, 3 different exhaust pipes, etc, etc, etc
Here are a few hints to help determine the production runs:
If it has an aluminum spacer [approx. 2" long]it most likely will also have the mushroom lifters.
If it is a late motor it may have the tiny 16MM carburetor [most likely will have "block" head]
If the flywheel has balance holes it is the better system and can have either the 6 or 8 pole stator.
If the side cover has "Whizzer" embossed it is most likely the ball bearing version [not my choice for long life]
Early heads have a very bright finish, but are rare.
Late heads ["LakeTahoe"] are very problematic and perform poorly.
Late heads ["heart pattern"] are decent but also rare and hard to identify from outside.
Muffler inserts [when made correctly] on most late motors are good, however early versions steal a lot of power and shoud be replaced or removed entirely.
Rear brakes vary, and some are very good and some are not.
All coaster brake wheels should be replaced [I always use vintage hubs on my personal wheels]
Band brakes make a lot of sounds, but don't do much to stop the bike.
Expanding drum brake rear wheels are the best of the bunch.
All manual clutch systems will make you "crazy" trying to make them work, and all the automatic clutches need to be upgraded or replaced [$125.00 to $229.00].
Best information I can offer without knowing all the facts.
Whizzers, old or new are in a world of their own. Once you ride a Whizzer you can better understand their sales motto, "Ride one and you will buy one".
While it is true, ALL new edition motors need several upgrades, in the end it is worth the effort, sadly some versions need more upgrades than others. None will survive without some changes, but all the information needed is on this site. If you need additional information, just ask.
Have fun,