If it is new parts that you require to make good the recoil then I wonder if http://www.meetens.co.uk/products/jap_engines.html
can help. They do tend to be exceedingly knowledgeable on their subject. I have bought Villiers and MAG spares from them in the past.
I also wonder if a posting on http://www.tractorbox.co.uk/forum/default.asp
the forum of the Vintage Horticultural & Garden Machinery Club may help. I often see much helpful documentation being talked of there.