A gz 250 tank is 3.7 gal. Has anyone ever considered changing to one of these. I wonder how it stacks up? 3.7 vs. 2.77 is real close to a gallon. It puzzles me that they'd put a smaller tank on a bigger bike. Maybe a style decision or something.

Gus

This Wiki thing claims the tank is 4.2 gallons on the GZ125, 3.4 gallons on the GZ250. Not sure why the difference - Some eBay listings show the same tank fits both bikes. 
https://en.wikipedia.org/wiki/Suzuki_GZ_series

The bottom of the GZ250 tank doesn't look like it has enough room for the coil/decompression solenoid, flasher relay, etc. that is mounted to the frame tube.  The wide area under the tank where the speedometer is located has a lot of stuff mounted to the frame on the stock Savage.

GZ250


LS650



One member used a 3.6 gallon VN750 tank - unfortunately he provided no information about the work necessary to make it work.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1245897456

However this thread shows the bottom of the tank, and it is obvious none of the mounts will work.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1438362708/2#2

Making a tank fit the Savage requires work....you have to make front and rear mounts, the petcock may not be in a good place on the replacement tank, and the frame/decompression solenoid clearance under the tanks is sometimes a problem.

I used a GT750 tank on my Cafe bike.  It required making new mounts, I had to become a blacksmith for a while and make a deeper frame notch in the tank by heating and hammering the tank, I had to relocate the petcock, and I had to cut a section out of the tank and weld an offset in to provide clearance for the top of the engine where the cam chain housing is located.