Aermacchi engine modifications
In the early 1970s I built a four valve water cooled top end for my Aermacchi racer. Classic racing rules generally prohibit four valves and/or water cooling for that period.
I did a lot of port work and flow bench testing to bring road bike ports up to racing standard. The exhaust port was very long which picks up a lot of heat to feed back into the head, so I shortened that and substituted a steel stub. I don’t like oil leaks and effort was put into using O-rings wherever possible to prevent that.
This sort of work is never finished and continues…..