Conversion like from the 80s on my GT 80

So, now have all the parts together for my conversion : steel flex brake line, box swing ( you have to change appropriately ), spring legs, machined cylinder head and 24 Mikuni carburettor. The only thing I no longer grow at my age is the Polybauer full cover with the M handlebar. The then registration of another translation ( 14/37 ) = 87 km/h had the GT already.