Go here: D:\NewSite\HondaRacer\mainpage.htm
Look in the 175 racer section, then the engine section, then ignition.
These photos show the plate but not the seal carrier...which fits inside the large hole. It has a "step" in the back to locate it in the hole, then a recess in the front to accept the seal. It is attached by three or four countersunk socket head screws that enter from the back side of the plate and into the back side of the seal carrier. I put a small amount of sealant around the back of the carrier, place it in the hole and screw it down from the back.
The plate is about 3mm thick 6061, the carrier about 3/8" thick. I sourced out a proper seal for the crank before I designed the carrier. I had emachineshop do the parts in batches of ten. I scanned a side cover gasket and traced it in a CAD program to create the necessary drawings for the plate.
Works great, both Mary and I have been using them for close to two years now. Will typically leak a couple of drops during a race that is contained by the engine cover. Which is fine by me as it keeps the seal lubricated. And by a couple of drops....I mean just a couple of drops.