My 16 year old Son wants to improve the performance of his 50cc Moped by de-regulating it. Is this legal ? Would it affect his provisional license or his insurance cover ?
Legal, not to carry out the derestriction but for him to the ride it on a provisial license then yes it would be.
Not sure about the insurance, but it would certainly be against the terms to make the change and not tell them. I'm not sure of the legal position of having insurance on a vehicle you cannot legally drive, but I'd imagine it wouldn't be possible.
Obviously illegal to ride it after being de-restricted - just as WoWo says. Also the insurance will be invalid - in the event of any claim there will certainly be no chance of a pay-out because basically ANY modification has to be notified. I have seen many reports of compensation being with-held in total write-offs where there was not even any blame attached. The moped WILL attract the attention of the police and it would be quite in order to throw the book for being Unlicenced, uninsured.