Google "Romeros motos". It is a bike shop in Barcelona that still makes the part you are after. I will be calling into that shop in march 2011 (when I travel to europe) for that same part . Plus numerous other bultaco fontera goodies, although I haven,t told the missus yet as she thinks we are going on a romantic holiday....Your other option is to make one yourself. Believe me ,you wont find one here unless you are very lucky. I just got a pipe for my 370 mk11 "m215", or the "1978 blue bike " as you call it. It took me 3 years to find one one Ebay, but I was prepared to wait as I was busy rebuilding a 1978 Gold medal frontera, thats the "gold bike"..ha ha .......anyway mate good luck...lyle.
