Did the 1971 CB750 K1 have orange or red rear turn signals?
Think I answered my own question
red lenses Honda 750 turn signal lenses Special note: red turn signal lenses Honda 750
Should you run across a red turn signal lens on a US 1969-78 K-model:
In America, red was not issued on 69-78 US-sold Honda 750s.
It was in some other countries and it was/is available here after-market.
One available 1975-1978 (larger type) red turn signal lens is 33402-377-810.
NOTE: some states do not allow red lenses facing front.