JT
I have heard that the 4st requires some periodic adjustment of
the valve train as it is a solid lift valve train. How simple or complicated the adjustments are I have no idea as they probably
vary from manufacture to manufacture. In an automobile engine
that has solid lift valve train the valves would generally need adjustment once a year @ 20,000 mi. per year. The automobile engine rarely see's RPM in excess off 5000 RPM. If it did it would require more frequent intervals of valve train adjustment. I'm thinking about going 4st myself but until these questions are answered I'll stick with what I have. though the 4st sounds so awsome. Just food for thought.