This is a hard to find part which fits the Douglas Rod type and G, it holds the flywheel fan cover plate on and is top quality, produced in Italy by Mauro Pascoli.
Douglas Vespa Rod Type & G Fan Cover Wire Clip
Due to the poor fuel quality in the 1940s generally only low compression cylinder heads were used, so as not to endanger the durability of the engines.
"Nagy" High Compression head for Douglas Rod/G & early Piaggio/ACMA single port engines