The real Honda Passport is not some third rate rebadged Isuzu Rodeo, which was purchased only by status hungry clowns who wanted that "Honda Quality", but were too stupid to realize that Isuzu is one of the worst brands on the planet. Nope, the real Honda Passport is a small motorcycle which has been produced by Honda (and now several other companies) continuously since the 1950s. In fact it has the single largest production run of any vehicle ever made, (as long as you count all the many variations).
The Passport was known under many different names, but the Passport name is the one that most of the world has had since the 1970s, so that is the one we will be using. However some people still refer to this model as the Honda Cub or Super Cub. The bikes underwent a small but continuous evolution, from time to time it would change names, and different companies would get different models. All of them were step through scooters though. A step through scooter is a motor scooter that does not have a flat foot platform, but instead has traditional footrests like a normal motorcycle. But it does have the traditional leg guards and underseat tank that most motor scooters are known for.
There were 3 common engines in the Passport/Honda Cub, the 50 CC, the 70 CC, and the 90 CC. Believe it or not the engines are actually named after their displacements, or at least they are given names close to their displacements. The 50 is actually a 49, the 70 is a 72 and the 90 is an 89, but I think the Japanese prefer round numbers on their motorcycles. Every Passport I have ever seen has been equipped with a clutchless transmission, it requires manual shifting, but has no actual clutch lever. I quite like that setup, it is easier to deal with. As far as I know all the original Honda bikes came with 3 speed transmissions, but there were versions of the engines available in other Honda products with 4 speed transmission as well, and some got transplanted. In fact all the engines could be swapped around (as could some even larger displacement engines available in some of Honda's ATVs and dirt bikes). Currently there are several different companies reproducing Honda's engine designs, with both 3 and 4 speed transmissions, both clutched and clutchless, so you have a lot of choice if you need a new engine for your Passport.
The Passport has a whole lot of advantages when compared side by side with Italian scooters (and one significant drawback), like the Vespa. The biggest advantage is gas mileage, which was between 95 and 115 miles to the gallon (this varied with year and drivetrain). The second advantage was the fact that Italian scooters break down if you even think about riding them, while Honda's bikes are pretty much the best on the planet. Finally, the Passports used actual 17" motorcycle wheels and tires, while other scooters used little fat 10" tires that have terrible handling qualities.
Of course there was that one pesky drawback, and that is top speed, there does not exist a factory made Passport capable of even beginning to keep up with highway traffic. The 50 CC models top out at 35 miles per hour, while the 70 CC models can do 45, and the 90 CC models can get close to 60, but all those top speeds are for windless conditions on a road slightly downhill. You can certainly build yourself a highway capable Passport (using a 110 CC engine with 4 speed transmission and speed parts), but it wouldn't be safe, as they are simply too light for highway driving.
In the United States the most common Passports available seem to be 70 CC models produced between 1980 and 1983, they must have sold really well those years, as those are the only ones I ever see. 1983 was the last year the Passport was available in America, but Honda continued it in other areas up until the mid 90s. In the mid 90s several Chinese motorcycle manufacturers began producing it under license (with mildly different names, most popular model seems to be the NP Passport, which is exactly the same except for the headlight). I can't read Japanese, but it appears that Honda themselves might be producing the model again, as it is back on their Japanese website. The last actual change in the Passport evolution was in 1982, when they went from a 6 volt electrical system to a 12 volt one. The current bikes are identical to the 1982 models, with the exception of the headlight. A lot of 12 volt parts don't fit 6 volt bikes and vise versa. Normally this works out in favor of the owners of the 12 volt bikes, as you can order any common replacement parts for those from Asia. But it can be a nightmare when you need an uncommon replacement part. My personal scooter is out of commission at the moment because it needs a handlebar bracket to fix some crash damage. The handlebar bracket off the 6 volt model doesn't fit, and it isn't a normal replacement part so I can't order one from Asia. I may very well have to buy an entire bike to get that one part.
I simply can't say enough good things about these scooters, I am on my second one (both were 1983 models), the first one I stupidly sold, but I won't ever be giving up my current one. Or, to be more precise, I plan on owning a Passport for the rest of my life, although it might not always be the same one I have now. They are fun to ride, they get a lot of attention, and they can save you a fortune on gas mileage.
Update. I am now on my third Passport. I found a sweet 1981 6-Volt model to tide me over until I can find a handlebar bracket from a 12-Volt model.