Here is a pic of my set up, round to better memic the crank case of old engines, I was going to run it on the inside but found out that by placing it on the outside I got a much more authentic look matching the shapes of the Indian mounts and then I'll dress up the red plate with some stuff I found at a Motorcycle junk yard, here is an oil pump cover I found off an old Triumph, it will go on the right side of the crank case plate and the plumbing will be connected to it for an electrical wiring tunel to the inside of the Faux crank then up to the Jaguar coil wich I'll fabricate a couple of Chinee engines magnito covers for a faux magnito box in front of the engine to house the coil and electrical connections.
If you don't have a motorcycle junk yard you can go to a 99 cent store or thrift store and get a couple of SS ash tray's and mount them in the color that the bike is going to be.
You could even polish the crank plate(not mounts) mask off some 1/4" lines then scotch brite over exposed areas to give a billet look and add even more depth and detail to it,I would experiment on a different piece first, you'll see that the possibilities are endless.
Looks good! experiment a little