The 500/4 in my avatar had a 550K34 tank. But as mentioned below, the tank is longer and wouldn't fit with the 500 seat. I bought a 550 seat and they matched up well - other than the 550 seat hinges were in a different place from the mounts on the 500 frame.
Steve and Caferacer550 - are you quite sure a CB550K tank won't fit on a CB500?? Maybe it is the CB550F tank that is different length?? I know they look different (gas filler; emblem attachment); maybe they and their seats are only swappable between the same model??
I have two CB500 tanks and one CB550K tank; they measure the same. I get 18" from the inside rear of the front tank mount to the rear edge of the rear tank mount; and 19 1/4" measured along the top of the tank from the front tunnel edge to the rear edge. I only used a carpenters tape measure; and only one tank has trim, but those numbers should be pretty close.
One of my tanks is a NOS dealer shelf queen; one dent from a dropped tool. Not too bad, but HTH do you pull out a dent??
