One of the things we do with all of our port jobs is to open the throat of the seats to a given percentage of the valve size. This really increases flow past the seat. These older heads sucjh as the sohc Honda as well as the KZ Kawasakis had the seat throat too small for the valve size for optimum performance.
This is included in all of our port jobs, and is an option on valve jobs only.
Virtually all of the newer hyper bikes, busas, etc. now come from the factory with this mod.
The photo shows a 750 with the intake seats bored before porting.
