The gearbox sprocket would be a good starting point
My dad took me to the Earls Court motorbike show when I was about fifteen. (C1961) There was a red Garelli on their stand, oh how I lusted after that 'bike. Dad couldn't get me off it. He often reminded me of what the guy working on the stand said to him ...
"If it was my bike to give, I'd give it to him, just look at him"
Gearbox sprocket was not welded on Micky! I think i got a good one mate!