What are the numbers off the plate on your mag. Just want to make sure which mag you have. I have a few spare magnetos and some various parts. I might have an extra cap. If I only have one, that's my spare π. If I have two I could part with one.
Dan, perhaps this will help. A great source for parts. http://www.standardmagneto.com/
P.S. the cap assembly part number is 5S9109. This is for a late model D2.