Gas/Fuel tank replacement/mod Ideas....

I have an 82 Maxim, making it into a bobber. Searched the forums and cant find any ideas about tank mods. I was thinking of using a different/smaller tank. Has anyone used, tried or know of a tank from another bike that ban be modified to fit the XJ frame? Also, Do I still need to use the stock petcock in the new tank? I would imagine so since its designed to run off the vacuum from cylinder 3.

I have an old motorcycle parts store in town, mostly metrics and I can browse through it on Saturdays. I am going to take measurements of the opening of the XJ tank and the mount points to see what I can find thats close and see if I can make that work. I have never welded before and looking forward to it, but nervous about doing so with a tank that had or may still have gasoline in it! lol
Also, I was thinking of relocating all the control buttons/switches to the center of the tank as long as I can get wires from under neath to the top without affecting the integrity of the gas tank. I saw a guy relocate them to where the side panel was on the left side, pretty neat and really cleaned up the handlebars. So even a two part tank could work I am guessing.

Thanks for anyones ideas/help.

 

The only info ican give you is regarding the use of the vacuum on the inlet manifold.
I run 2 XS11's both with XJ1100 ignition and carbs, both use universal fuel taps that don't have a reserve setting or vacuum, and i just run them both in the ON position or PRIME, and have had no problems.
I always make sure that i turn them to the OFF position when not running because it can cause fuel to overflow from the carbs into the crankcases.
It can also act as a warning sign that the float needles and seats are worn and need replacing.
Sorry that's all i can tell you.

 

If you get an on/off petcock then there is no need for the connection to engine vacuum on #3. Just cap it off like the others.

A tank should be purged before welding. There are a number of ways to do it.

 

Thats what i needed to know. Thanks Iwing.

 

I've seen a V-Star 650 tank on a 700Max, a Suzuki Savage(S40) tank on a 650Max and a Honda CB tank on a 550Max.
All the above required some mods.
You could also do the Harley split bob tanks, but the problem will be the width of the Harley and V-Star tanks at the seat. Seating position being on the rear of the tank and a wide tank at the rear will make you fell like your riding a horse.

 

Not so. It could ENABLE this happening; but if it does it indicates a carb float issue. A carb float malfunction IS THE CAUSE if this happens.

The petcock doesn't cause overflowing carbs.

 

Is there a section of the backbone removed just behind the petcock in that first picture? It looks like a plate has been bolted across the space created. If that is what you have done, you need to fix that. The stress put on the frame at that point will cause it to collapse. We don't want you becoming another statistic.