Motorcycle Repair: valve covers, ryan austin, bill silver

Question
Hello Bill-
I have a 1973 cb550 and i just reciently got it running.  As i was going to adjust the valve clearence i noticed that on 3 of the 4 intake valve covers it looked as though something had been hitting the last thread of the covers.  Im not sure if the rockerarms are able to come up this high?  It also looked like on of the valves was awfully high as well.  I dont know if the last owner tried putting in new valves or not.  Is it something that maybe able to be fixed just by tighting the cam chain, or do you suspect i have a serious problem on my hands.  thanks for any info
ryan austin tx

Answer
Ryan, could have been that the bike was run with loose locknuts and they backed off and started eating the threads... kind of a longshot there, though.

If the threads on the adjuster screws are all not fairly even in length, then you could have problems, there. You mention valve being high... did you mean the end of the valve stem or the end of the adjuster screws?

There was a tech service bulletin on early CB500s for the rocker arm shafts. The originals were separate pieces and they would work and spin in the cover bores, causing a lot of valve clearance issues, of course. Replacements were long versions that screwed into the covers and caught two rockers at a time. If you have loose rocker pins, then that needs addressing. If any of the adjuster screws are very short, then you could have worn cam/rockers, too.

This has nothing to do with the camchain, so if you have doubts about the positions of the internal parts, you may want to pop the rocker cover off and check the cams, rockers and valve stem height. There were lots of small stem valves used then, with different lenghts in Hondas of that era. Someone could have put an incorrect one in or perhaps the valve seat has gotten loose or is damaged.
You can do a whole top end job on this engine in the frame.

Don't go riding until you are confident that the motor is okay...

Bill Silver