Contrary to the beliefs of many one-make enthusiasts no manufacturer ever made a bike which was devoid of design errors. Likewise, the suppliers of ancillary equipment had their own problems which often compounded the manufacturers’ errors. Add 50 years of damp & deterioration, the benefit of hindsight, improved materials & technology & we have the opportunity to improve on the product of Mr. Parrilla. The Hicam Parilla engine was an innovative design for its day with many unique solutions to problems which other marques handled in a more conventional (& some may say heavy handed) way.
Here we will consider the improvements we can make to the engine & ancillary equipment. If your bike is for show & light (or no) road usage then these modifications will be of no, or little, interest. The OE (original equipment), if in good condition, will be perfectly adequate. If you are considering track use, regular road usage or entering an event such as the Motogiro D’Italia then they will be worthy of consideration.