The G-Man we tried is 7.5" long 4" wide 9" OAL length including valve. Looks like the pic you sent is super tight as well. But I think ours is a bit closer. and the tank I mentioned won't work. Thanks for the pics
I bought a tank from JC Specialties which mounts to the steering post and stands upright. I think it's 2.5 qt.?? It has the clamp mounted the tank and is an easy mount. I'm pretty sure it will fit your application.
We mounted our tank just ahead of the engine by using one of the stamped old style engine mount butterflies through the frame rails to the back of the tank, then off of the right side nerf bar spud with a typical weight bracket to the front just to help stabilize it and limit any movement or tendency to twist. The tank didn't seem to flex much if any and it allowed us to use a tank we already had. This was on a Falcon kid kart, so I understand that it has a bit more room than some of the more popular or metric kid karts. Now, if you don't feel real comfortable about mounting the tank right ahead of the engine (rod breaking, etc), make a simple firewall and bracket that to the backside of the tank as a sort of scattershield. When we first put our kid kart together with the JR LO206, I didn't even think of this, but in retrospect, that would have been a fine idea (just in case.)
Keep in mind that these things are absolute misers when it comes to fuel. We could run probably 5 full race nights on one tank of fuel (2.5 qt tank)! You could probably get away with a large catch tank as a fuel tank.
I don't see anything in the rule book as to where a tank should be mounted. I would like to mount behind the seat or on the left side of the seat. Does anyone know of any rules regarding mounting? Ideally I want it in front of the steering uprights.. but that may not happen. I can get creative with the size... Maybe an NOS drink bottle... lol
Many years ago, I had a tank mounted in front of the engine similar to the way I described here because I was using a big tank on an open and didn't like how it fit our chassis under the steering column. At that time, I was told in pre-tech that the tank had to be mounted between the frame rails. Because of the unconventional design of our Vector DO chassis, the tank would overhang the main frame rails anyhow, so I was allowed to mount the tank this way. The one thing that was definitely out was to mount to the nerf bar, or ahead of the pedals for obvious reasons.