Are you trying to figure out a saw’s originality? If this is your intent, post a pic here of the saw for an opinion.
I’ve been around a few of the model. I’ve never seen a clear tank on an 026, only an MS260 with the flippy caps.
The red lever 026 were the very early ones. The 024’s usually came with black levers. An original red lever 026 has no decomp valve and higher compression than the later saws because of a smaller combustion chamber. I’ve found the squish and timing to be about the same in all of the 44mm 026/260 jugs.
If you post the SN of the saw in question here, someone may be able to tell you the production years. 026 were produced in Virginia Beach USA. The 024/024S were generally West German, so pre-1990.
