In UK yes if you have been examined under the Direct Access Scheme and have a full A category licence. However, the bike must be restricted to 25kW(33bhp) and the power to weight ratio must not exceeding 0.16kW/kg. Information is taken from the DVLA website.
Not knowing where you live and ride the 125cc I can not answer your question exactly. Different state have different rules, but most all state now require a separate or a addition on your car license to operate a motorcycle In Texas where I live car license (Class C) is not acceptable for motorcycle. Here you would need a "M" addition to your current license. The "M" addition requires both a separate written skills test and a driving skills test to be legal for motorcycle. Motorcycles under 99cc and with automatic transmission are classed as mopeds and require yet a different driver test and license or addition to your current license. It would be a good ideal to check with your states department of licensing and registration to be absolutely sure of the requirements in your state or location.
Off road, as soon as you can reach the pedals. On road, as soon as you get your motorcycle license.
The A1 is an A road so technically yes, however you cannot join the M1 unless you have a full and current driving license for a motorcycle and the bike is over 50cc.
The legal age in the UK (Cornwall) for riding a 50cc moped is 16, riding a 125cc is 17, however at 17 you can take your full bike license, and ride a more powerful bike but it must be restricted.
Scooters above 49cc are classified as motorcycles. You would need a motorcycle endorsement/license.
You have to be 16 to ride a scotter. But to ride a 125cc you have to 17
Yes, that is a good size bike to learn on. If the bike is street legal you will need a motorcycle license.
No. That's a motorcycle. Motorcycle are to be ridden with the cars.
Yes, provided you have a licence for a 125cc, or provisional licence and are displaying L plates.
After a Compulsory Basic Test, CBT, you can ride a 50cc moped without 'L' plates or up to 125cc bike/scooter with 'L' plates.
About 125cc
To legally drive a 125cc motorcycle anywhere in the U.S. you need a class M drivers license. In the UK, you can use your car license with L plates, but you have to complete the CBT every two years.
in short if you passed after 2001 you will need a Full CAR