Hey husabutt,
Thanks for the great picture! I had tried earlier to find out what year mine was. I posted the VIN and didn't get the info that time but no big deal. I have not got the title yet from the previous owner as he is out of town most of the time. He said the title says "HusaBERT" and it's listed as a 1997. But he also told me it was a left over. So could be a '96 or even a '95 I guess. I do not have the filter cover like the one in the photo. I have a black plastic screw-in plug identical to the oil fill plug, and behind it is a tubular screen and spring only. I have an owners manual of the original 501 and the pictures in there are the same as mine.
I guess mine must be older than a '97.
I also noticed your tank is blue, mine is yellow. Is that the factory color for '97?
Thanks,
Volvonut