Hi Emilios,
I ran a 650 triumph unit in my A10 for a while. The only issues were engine mounts. Once u have the chain inline fire up the grinder and mount the engine. U will now have an alternator and points so the wiring needs a little splicing. I used a Honda 50 switch, zenor diode with heat sink and a cheap rectifier. (Normal triumphs setup)
The oil tank will work fine. I mounted my coils in the tool box along with ignition and other wiring connections.
I’m on holls at the mo and won’t be back home till mid Jan. I’m sure I have my old engine plates somewhere. Will have a root when I’m back.
Just to say, by the way, the trumpet in the Beeza went like a hot snot 👌