Increasing 06 450f Fuel capacity

I have a natural IMS 3.4 gal desert tank on it now but do not like the fit, and finish compared to the stock black tank. A few months ago I read a post about stretching the fuel tank with hot water and air pressure, and getting over 3 gal with this. I have tried searches but cant come up with anything. Anybody remember where it was or have done this before? :applause:

I just found the thread. :applause:

So does it work????

Just got home from the track, I am going to wash the bike and then try it out. Will let you know tonight.

Ok I tried the boiling water 3 times and have gotten it up to 2.01 gal after cooling off. It is a little difficult to keep it from expanding on the shrouds too much, since I am trying to keep the narrowness of the stocker I am going to use a heat gun to work on certain areas where there is room to expand on. I may still keep the IMS for the longer trail rides, since all of my riding buddies are too damn cheap to buy a bigger tank. I always have to bail them out. But if I can get around 2.5 gal I will be stoked .

WoW sounds cool post some pics and end results when you finish.

I have made 3 atempts at expanding my stock tank over the weekend. It has gone from 7 litres to 8...thats it. I guess I should shoot more air in, just kinda freaked out over blowing up the whole tank of boiling water into my face ( Iwear goggles when experimenting).

My process: Add 6 litres of boiling water, wait 5 minutes to let the tank plastic really heat up, Shoot compressed air in through the cap (my compressor is set at 70psi, i give it 3 quick shots and the tank balloons), keep adding air as the air in the tank slowly seeps out through the cap, run cool water over the tank for 10 mins, then I drain most of the hot water and add cool water and blow the tank back up so that it cools in a larger position. It just seams to come right back to its original size. Plastic has such a good memory. Have you guys measured the size after 2 days of cooling and sitting in your garage? Mine was at 7.5 litres....thats 2 cups bigger than stock.

Most of my expansion is going straight outwards on the shrouds where I want little expansion. There is only a little forward expansion.? I would be so happy if I could get it to cool at 9 litres!!!

Boiling water. 1.25 gallons of it. right from the stove into the tank. It is super important to have a good seal on the cap/air fitting! you have to expand it with the air and let it sit until the water has cooled off entirely!! If the pressure leaks out while the water and plastic are still warm then it will not work!

I think that it is possible to get around 2.2-2.3 but that is max of what you should expect. I rigged up a new air fitting so that it doesn't leak but I have not tried it yet. Mine leaked on the first try and it was a scramble to try and keep the air pressure constant and try to cool off the water at the same time. The air pressure has to stay the same untill the tank has completely cooled. I can't stress that enough. your wasting your time if it will not hold air pressure.


anyone have any pics also how buly does it get on the sides and how does everthing fit up afterwords??

It really is funny how everyone wants a picture of a black fuel tank that has expanded maybe 1/4 to 1/2 an inch!!! You can't even tell a difference hardly in person. I got about 20 private messages asking for pictures on the original post 2 months ago even though I had stated clearly that you really can't see a difference!!

The only benefit to a picture of this would be a good leak proof air fitting set up so every one can see how to set up the air fitting. other than that pictures are worthless.

Not trying to be harsh. It's just funny!!


Can you describe your leak proof fitting to the cap. I have tryed a tapered extension that fits on to the air blower (pistol grip that connects to compressed air). Fit the tapered piece into the hose and shoot the air in, however tight I get it at the tapered-hose connection, it always seams to leak at the hose-cap connection and it looks impossible to put a tridan clamp that low on the hose-cap fitting.

The other method I have had more success with is putting a 1/4" adapter onto the air blower which then fits very tight to the plastic nipple on the cap, however, once I have shot some air into the tank and the pressure builds, the air will leak slowly out of this connection. Please help! I really think that getting 2.1 - 2.4 gallons out of the stock tank is perfect. Thank you.

So even with the shrouds on and everthing you can't tell tell the difference??? Pics of the air shutoff would be great.

I cut the shrader valve off of an old inner tube. I attached a chunk of fuel line about 4 inches long to the vent nipple on the cap with a small hose clamp and inserted the shrader valve in the other end with a hose clamp on that. Use a normal air chuck that you would use to fill your tires and off you go!!! It is a much better compromise than running the IMS tank.

It does not take much air pressure (3-8 lbs maybe) 1-3 short bursts to get the tank to the point that you want it. Go a little farther than you want because the tank will still shrink back slightly when you let the air out. WAIT over night to allow the water and plastic to cool completely before you let the air out!!!!!

I can't load pictures they are to big and I don't have a way to shrink them so that they will load.


You offroaders are a trip........... :excuseme:

at least your not drilling holes in the frame to find air spaces to fill with gas.....anyone remember that mod? :bonk:

please show a pic of a bulged out stock tank.....I got to see it! :busted:

Sap is right, the air tight fitting at the cap made all the difference. 2 days after blowing up my stock tank for the 3rd time, I now can carry 8.2 litres instead of 7. This will be perfect for racing, I am sure I can get 50 kms in now for a ride. You can't see a difference from stock, in fact I thought my tank had cooled down to the original size. When riding, you can't feel a difference either. I think the tank is just 1/2" larger all the way around. This has been a great, free mod, thanks Sap.

This has got to be one of the best free mods I have done. Worked great I just had a C clamp to pinch the vent line off then I put air in the outlet line with the valve.

Also with my friends 05 450 sitting side by side you have to look real hard to even tell the tank is bigger.

Anyone think this might work on the steel frame tanks?

i wouldnt mind bein able to hold a little more gas in my 99, but im afraid the sides would bubble out and itdd look retarded.


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