If you are looking for high end takegawa or kitaco parts, i usually buy all of them from webike japan. As for the engine posted above, those covers are actually not the graft ones, they are chinese coolers and they are mounted on top of a Honda Nice head mounted to a stock style engine and should be available off the webike site. They do make them for standard engine heads as well.
Just for fun, I actually put these finned covers on my stock Honda Nice engine to determine their overall cooling capabilities. I usually follow the same standard procedure...warm the engine up good and then run a very specific 10 mile loop and monitor the oil temps. They are pretty effective, quite honestly. Over the course of the run, the temp was only 2 degrees C higher then my use of a traditional radiator style cooler. The left side cover is just a finned heat sink as are the valve covers. However the right side is actually an oil pass through...oil goes into that finned cover and circulates around. It doesn't spend a whole lot of time in there for sure, and honestly, not sure how much cooling effect it has there. What these things really do is create larger surface areas for air to hit and hence cools the head quite a bit, and therefore the oil that passes through the whole head.
These coolers in that picture will not clear the downtubes of a stock CT70, but the graft ones that are 5-row supposedly do. To be honest, if the engine is stock and properly tuned, you won't be able to overheat it even if you run it at 9k for an hour straight. they are designed to take that kind of beating. Really, the honda Nice would take that beating as well without worrying about it, but I like to keep the temps just under 100c just enough to steam off any water in the crankcase.
