I just finished installing the RPVs in my original MC. Not too bad of a job.
Here are a few diagrams showing the RPV (check) valves:
I couldn't get the supplied 6-32 self-tapping screw to 'start', so I drilled & tapped the existing seats.
A little grease (Permatex brake caliper grease that is compatible with all brake system rubber parts) on the drill to capture the brass chips:
Same goes for the tap:
Tapping the seat:
Install the tube nut, then install a 6-32 screw long enough to engage all the threads you just tapped:
Hold the screw from turning and back out the tube nut:
Here is one of the original seats after removal:
Clean everything thoroughly, then install the RPV, then the seat, then the tube nut, and tighten the tube nut until the seat bottoms out. Do the same on the other port and you are done. The finished project:
Sorry I forgot to take pictures of the actual valves. When I got to that part I guess I got a little anxious to get everything installed.
Thanks again to Steve for all his help.