You might want to check the choke cable and adjustment also. It uses a cam to step up the idle a bit, but should top out around 2500-3000 rpm. It should also slowly reset itself to the off position after a bit.
Hope this helps.
Luke M
(missing his bike, which has been disassembled for 4 weeks now)
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.