Physically, its merely a matter of changing the sprockets on the cam shaft and crankshaft to one designed for toothed belts, but from a mechanical designer's view, this makes no sense. Possibly, a belt would be quieter. However, a chain drive can approach 98% efficiency and a belt can not. Ultimately, a belt will need replaceing at the expense of removing a gasketed belt cover and all the labor required to get to it. An enclosed belt can not be inspected unless a port hole is provided. It does eliminate the seal on the camshaft extension. I would think that a belt tensioner is required, the same as for a dry belt.

Maybe this application is for a motorcycle engine. Look at the evolution of engine development in Japan and it seems they use motorcycle engines for their test beds. Several developments appear on motorcycle engines a few years before these are found in automotive engines (from Japan). To name a couple I know of: 4 to 5 valves per cylinder; Counter balance shafts.