1971 – In this year a new version of the Morini Corsaro Regolarità was put into production, the fifth and final type which used the new Verlicchi double cradle steel frame, more modern and lighter and with notable differences also to the engine (larger valves, lightened clutch, polished ports, dual external coils and a  Dell’Orto carburettor with central chamber.
The main design of the engine, with the exception of the larger cubic inch version, remained the same but the 100cc model came out of production. At this time the larger engine model was also made more powerful – it increased to 163,99 cc (bore 60 x stroke 58 mm) and used a new carburettor, a VHB 25mm diameter with an increase of 0.5 horsepower.
The cylinder of the “165” was evidently wider and square in form – it subsequently became known as the 'Testa Quadra' (square head).
The 125 cc model maintained distribution through rods and rockers with 2 parallel valves, the carburettor was 22mm and the engine gave 11 cv at 9,500 rpm.
Aesthetically, apart from the new Verlicchi frame and roundede petrol tank, other differences could be noted when compared to the previous model, such as the Marzocchi forks and shock absorbers, the steering damper, the rear 21 inch wheel, rear mudguard and the steel gonfleur and number carrier.

In the same year, for the top models the valve seats were also modified in order to create a kind of spherical chamber which allowed a performance increase of one horsepower, keeping the parallel valves (more reliable and less subject to breakage than the inclined valves). A further increase in power was obtained by using a different exhaust with a left side exit.
Thanks to all these great innovations the prize Morinis were enriched by the eplendid victory in the 175 class at the ‘Valli Bergamasche’ in Lovere (1st – 2nd June) by Alessandro Gritti, followed by a Emilio Capelli 5th and Ezio Dall'Ara 8th; in the 125 class the fifthe position of Pierluigi Rottigni is to be remembered.
At the six days on the Isle of Man (20th – 25th September) there were various official and private riders registered, all equipped with Morini Corsaro Regolarità models type 5, while the ‘Gruppo sportivo’ of the Fiamme Gialle (Sport Team of the italian army called Yellow Flames) made up of Carlo Paganessi, Alessandro Gritti, Giuseppe Signorelli, Pierluigi Rottigni, Bernardino Gualdi and Giovanni Collina all used type 4 Morinis, flat head. This was the last outing on the international scene of this glorious marque.
Gritti, Signorelli, Rottigni and Gualdi represented Italy in the Silver Vase.
The race finished with four gold medals awarded to Signorelli, Collina, Gualdi and Gritti.