- Joined
- Feb 17, 2009
- Messages
- 16,767
- Reaction score
- 16,090
- Location
- Beautiful Rockbound Coast of Maine
Ok Eric....you got me curious so I went the shop and dug through my old brochures too........and you're right...at least the older 80's with black and white stickers show the flat bottom filter cover.....note that it sits flush on the top cover, like a 621...but the round covers sit proud of the covers by 1/4" or so........makes me think (in theory) that the 80's initially used the 621 filter set up which was an exact carry over from the 601 and 751 but later found it to not have enough area to flow the larger 80 cc motor as well as a larger filter and so developed the longer filter with a correct cover (round) to be added to the later production 80 saws with a minmum of effort........this just my theory but knowing what we do know of Jonsereds propensity to us the same parts on as many varied models as possible it makes sense to me....