There's tons and tons of differences, what are you looking for in particular?
The PCX was first released in 2011. The US and UK version are basically the same, but everyone other than the US gets idle stop. The Thai market gets cheaper headlights. The airbox, engine, etc. are all the same as far as I know for the 2011s across all markets.
A PCX 125 ESP was introduced, and was exported to the UK for a fair bit due to regulations. It hardly existed in the USA, and is fairly rare to come across here. You can see from the outside that the airbox is different, but the entire engine is changed somewhat, including the exhaust. Even the heads are slightly different. The gearing is different in the transmission, and the variator is slightly different (though the variator is interchangable). It's slightly slower compared to the original 2011, but gets slightly better gas mileage.
The PCX 150 ESP was introduced, and gets better fuel economy than the PCX 125s. I don't think the UK got it due to the previous model being mostly for their market. It has different transmission gearing again, and a completely different engine again, including the exhaust. The body panels and seat are mostly interchangable from the 2011-2013s, with the exception of the fuel flap (and possibly the underseat bin?) as well as the wheels. Windshields that fit the 2013s will fit 2011s fine.
2015 introduced the new PCX 150. For the most part, nothing is interchangable. It's a completely different beast. Honda did a great job on the headlights, they're some of the best I've seen on a cycle.
All years have CBS, or combination brake system. That means you pull the left lever, and the rear drum brake actuates and 1 of the pistons on the front caliper actuates. The right brake actuates the other 2 pistons on the front caliper. Honda has deemed this braking method "safer," but that's open to debate.
I have no idea about hazard warning.
All PCXes other than the US market had the option to get an alarm. We don't get that, but can order it from Europe or Asia and hack it in.
Obviously, the US model has improper units (Miles / MPH), whereas the rest of the world has KM. I believe the US model has a catalytic converter and charcoal filter for emissions, which many non-US models are not equipped with.
I'm sure I'm missing something. That was just a huge pile of information; if you have anything specific, I may already know (or can find out from microfiches
![Wink ;)](./images/smilies/icon_e_wink.gif)
).