seca tank on a maxim frame?

will a 81seca 550 tank fit on a 83maxim 550 frame ?

 

Only sorta. If the rear mounting point does line up (and I'm not 100% sure it will) it will sit funny.

The 550 Seca and 550 Maxim have different frames so the seats and bodywork don't exchange very gracefully. The Seca had more of a straight line along the bottom of the tank/seat; the Maxim frame "dipped" down quite a bit to accomodate the stepped seat and lower seat height. As a result, the Maxim tank/seat/sidecovers have a downward swoop to them that's not there on the Seca.

See if these help; I did these for someone else who was contemplating the same mod... Note how flat the bottom is, even though the front sides curve down a little bit,

550 Seca tank dimensions:

 

thanks. most detailed answer i could have possibly expected

 

Im with Fitz on this one. I have a 81 maxim 550. I want and will replace the gastank with one that looks exactly as the one in Fitz's picture except for the color. Up untill tonight I couldnt figure out what it was from because the ebay seller's description was horrible. Anyway the stock tank on my maxim is about 2 inches shorter when compared to the seca tank (all obvious differences aside) I will have to relocate the bracket on the frame that the rear of the tank bolts to, and also fab up a set of airbox support brackets, because they are part of the tank suport bracket(if I decide to keep the airbox). The front tank mounts(buckets) do fit however but are a bit snug when compared to the stock tank. Also the curvature of the rear tank flange will contact the frame ever so slightly when bolted down and will need to be modified to clear. ill post up some pics of my project when I get to that point but aside from the above mentioned issues all seems to fit nicely. If you are just looking to swap a tank for the heck of it then id say dont do it and stick with the stock tank. But if you are willing to cut, weld, and fab up brackets, as well as a new seat, and other small odds and ends then go for it.