We have no reports from travellers on this particular route. US scheduled airlines are generally stroppy about shipping bikes (dangerous goods, etc.)
I would start with DAS Air Cargo, which does fly into Africa from the US.
"DAS Air Cargo USA proudly serves over 40 African and Middle Eastern cities, utilizing our DC10 as well as outstanding interline services with other international carriers."
They may not fly from SFO, as their website lists Orlando, Atlanta, Baltimore and Texas offices, although they do have an agent in California.
Their direct toll-free is 800-327-0212. The agent in Los Angeles is:
LAX - Air Cargo Promotion
5757 West Century Blvd, Suite 660, Los Angeles, CA 90045
Covered Area: California, Oregon, and Washington
"It matters not what goal you seek
Its secret here reposes:
You've got to dig from week to week
To get Results or Roses."
'One world, two wheels'