Easiest way to get the springs/valves off head.

[Raptor]

Making a tool is possible, I have seen several home grown variations that fit the mitsu head. Depending on what tool you have for the domestic heads, it could be modified as well, really depends on what it is. I believe there is an example of one online somewhere as well. As far as cheap ones go, I don't know of any that are all that cheap that will work. Mine was over a hundred.