I’ve lately been working on improving the performance of 90’s Ducati supersport engines, base horsepower runs about 75-80 at the wheel, which isn’t bad for an air cooled two valve engine, but people who race these bikes have been running up to 115-120hp. Most of the improvements are found in the head, modification of anything below that is really for reliability. Bruce Meyers, who has been building these engines for 20+ years, has been assisting me in my modifications, part of the plan being that I will eventually design and cast new cylinder heads based on our combined efforts.
The biggest modification done to the racing heads comes in the intake port, which is straightened out and made wider at the manifold, this increases the velocity of the intake air and allows for development of power in the higher rpm range, provided a proper cam is used. Bruce also uses larger valves, which require re-angling of the guides and seat bores by a combined 2 degrees. The exhaust port is left largely untouched, the reason being that the intake air is being drawn in by vacuum and whatever resonant pulse is coming from the intake stack, whereas the exhaust is being pushed out under high pressure, meaning the exhaust gas will tend to find its way out even with a less than ideal port.
