Fairbanks morse mag cap and rotor

I have a Fairbanks Morse magneto off of a D that was missing the cap and I would also like a rotor for it, as the one on there is cracked, I looked on this site in parts and other places with no luck, can someone point me to where I could find those parts, please thank you

You might try contacting Mainely Magnetos in Maine. Here's what they say about the use of a Fairbanks Mag in a D. It looks like a Fairbanks was ;used in 2 very narrow serial # ranges in 1928 and 1930.

Fairbanks & Morse
model R2
John Deere part # AC199R
application D 94,701-94,800 * D X67,500-X67,598 (1928 D experimental tractors)
* Note: The 1928 D experimental tractors "possibly" used the AC432R magneto
listed below, which is the same make & model of magneto. Differences between
an AC432R magneto and a AC199R are currently not known. We feel the
differences would have been minor.
Note: This magneto had raised lettering on its' rear side that said John Deere
Tractor Company Waterloo, Iowa. There were no external markings that
mentioned Fairbanks & Morse. The magneto was made by Fairbanks & Morse
exclusively for John Deere. It was referred to as a model R2 in all Fairbanks &
Morse parts and service literature.
Note: The exposed magnet was painted semi-gloss black. The rest of the
magneto was not painted. Due to the external timing lever that attached
to the rear of the magneto with a cotter key not being shown in any of the
Fairbanks & Morse parts listing we have for one of these magnetos, there
is a good possibility this item was manufactured by John Deere and
installed on the magnetos once they were received from Fairbanks & Morse.
If that was in fact the case, the external timing lever may have been painted
John Deere green.

Thank you very much for the reply and my magneto has raised Fairbanks morse lettering