no not all of them, i have a 2012 motofino 50CC and it didn't have it but they do have rev limiters in the CDI, the stock carbs that can't be adjusted are set to burn lean to pass EPA guidelines, some have restrictors on the exhaust gasket.
there are a few things to do. replace the CDI with an performance CDI (5 wires DC 6 wires AC) check the variator for a washer on it, the washer prevents the belt from going to the top for high gear. you can also put in lighter roller weights. check exhaust gasket to see if it is restricted. most state laws do not allow 49cc scooters to exceed 30mph do this at your own risk.
no
in the CDI (Capacitor Discharge Ignition) box, you can get an aftermarket CDI cheap on ebay, if yours has 6 wires going into it then it is AC fired, 5 wires is DC fired.
the rev limiter is built into the CDI, you can get a CDI without the limiter on ebay.
Get the wiring diagram for your bike. I downloaded a great tank gy6 service manual that matched both my 50cc 4-stroke tank and baja scooters. I found CDI modules had a yellow and green wire going to something called speed selectable unit... I assumed a rev limiter. I diconneted the wires to it first. The bike didnt run.Then I tried connecting the green and yellow wires together, bypassing the rev limiter, and it worked great, so i did it to both bikes.
on 5occ - 150cc gy6 qmb or qmj engines the rev limiter is part of the cdi programming.
50cc scooters are restricted to around 30mph here in the UK. They can be de-reg'd up by a few mph but you'll notgenerally get much more out of them. Weight and stuff are also factors.
You need a drivers license for scooter 50cc and below. You need a motorcycle endorsement for above 50cc.
There are a variety of different companies that make 50cc mopeds. One of these companies that makes well known 50cc mopeds and scooters is Linhai Yamaha Aeolus.
Generally the electronic ignition module limits the rpm Hi performance modules are available without limiter.
i believe anything under 50cc
In the battery box. you will see it unplug it