Valve cover leak -- a known issue, common to this engine for many years, easy to replace yourself, though.
Oil needs to be changed at 1,800 miles, as per the book, but I find it is quite dirty after 1,500.
Replaced every single light bulb, after 3 of 4 instrument light bulbs went out, this was at 12,000 miles, and 28 years!
The speedometer is 9 MPH over! 65 MPH on the clock is actually only 56 MPH on radar, and my GPS... Tried to get this fixed by a speedometer repair specialist, but it is too old -- no parts.
This bike (1979 CB750K) is reliable, with no issues yet, other than routine maintenance. I changed all of the fluids after I bought it, added an in-line fuel filter to replace the missing screen from the fuel petcock assembly, and I installed a K&N permanent air filter.
The bike is a bit top-heavy, and it handles sluggishly in town, but on the highway, it handles very well.
Acceleration is poor in 1st-3rd gears, but in 4th and 5th, she really picks up and goes. It has good response on the highway with one person, but it is noticeably less quick with two-up (57 hp @ 8,000 RPM).
I put matching Pirelli Route 66 tires on it last Fall -- SWEET! Virtually immune to cracked pavement and steel grate bridges... Handles much better now.
Thirty years old, but still largely factory original parts. The four-into-four exhaust is showing signs of wear, but it still functions, no rust holes through the outside casings, and it has a nice rumble.
It came to me equipped with a Vetter Vindicator fairing, and a nice, hard trunk. I plan on installing a pair of saddlebags, this Spring. The wife wants to tour Northern Minnesota, around Lake Superior, this Summer. We've taken multiple, 250-mile, weekend trips on it, and it has been almost flawless in performance.
The seat is not the most comfortable, after an hour, for me, and the rear is downright uncomfortable for the wife, but we are checking into a King/Queen seat cover, so this should be a memory in a few months.
The Honda CB750's of the 1970's were well known for their reliability, stability, and overall goodness. My 30-year-old bike, is living up to this legend's reputation so far. Cheers!