I came across this two-in-one ghost sign combo at 798 Eddy St. just off Van Ness Ave., San Francisco’s old “auto row.” The Pioneer Motor Bearing Co., with its jaunty arrow, is fairly straightforward. The older sign? I think it says Stark Motor Co.
Judging by the centered “six” circle and gauging the apparent width of the original sign, it looks like the first two letters are missing, and “Stark” is what comes mind. What do you think? Perception Filter is puzzled by this one, too.
In any case, in addition to SF, the company had six additional locations: Los Angeles, Seattle, Portland, Fresno, Boise, and Spokane. The best part of the sign is this painted Art Deco flourish:
Department of Everyday Visualingual 
very pretty
There are lots of cool ghost signs if you know where to look!
cool
The font reminds me of the old Lenox Motors sign in North Avondale. (now gone)
I don’t think I ever saw that one.
Wow that amazing. Retrospective of being century old companies
Pioneer Motor Bearing is still in business and still ran by the the same family that started it in 1920. They are now located near Charlotte, NC. Pioneer Motor Bearing Co. repairs and manufactures fluid film babbitt bearings for the power generation industry and naval/maritime applications including the US Navy. http://www.pioneer1.com for anyone interested.
Here are some more historical photos of the building and sign: