Adding Volume to Plastic Tank

Hello All,

I have an IMS tank for my bike and want to add some volume. I remember reading about using some heat and compressed air to get a little extra volume in the tank. Could anyone who has done this, post a little info on the procedure you used and what the potential pitfalls are?



I imagine putting air pressure to it while warm may swell it a bit, but seems pretty risky, and not much gain, I wouldn't think ... look around, maybe you'll find someone to buy your tank, or swap for a bigger one .. :thumbsup:

dude, thats rediculous.....some areas of it would be just a degree or two hotter causing that small part to bubble out much easier. also, thicker areas would not expand like thinner ares (even just a thousandth of an inch) DONT EVEN TRY IT.

From what I've heard you can fill it with very hot water while it's mounted on the bike, shoot compressed air into it(probably via the vacuum port on the cap) and it should expand.

I've done this a few times and yes you can get a significant amount of volume depending on the tank size. First you need to boil enough water to fill half the tank, the hot water helps to make the plastic moldable. After you fill the tank you will need to take your air compressor and blow in through your vent hose slowly.

Keep the tank on the bike otherwise you will distort the tank a bit and make it difficult to get the tank back on. You need to be extremely careful how much you blow it up, be conservative. You will see the the sides start to balloon out (be careful with this part). Once you have blown it up you need to clamp off the vent hose for a 24 hour period. Be sure your gas cap is on tight enough that the pressure isn't leaking out.

When your 24 hours is up you will need to repeat the process. The tank will hold this shape for awhile, but it usually returns to normal size and shape after a few days. I have done this on a Clark 3. something gallon tank and I got maybe a little better then a quart.

If your doing this for a permanent solution for extra volume, you probably need to invest in a bigger tank. This is only good temporarily.

I have friends who have taken one more step using a heat gun along the seems with no problems.

Thanks for the replies, the boiling water technique sounds reasonable enough, but the temporary nature of it is news to me. That probably doesn't make it worth it. As a note, I am looking to expand a 6.6 gallon IMS tank for a KLR 650. I remembered reading about the technique in the XR forum, so that's where I figured the knowledge was....


If a 6.6 gallon tank doesn't do it for you, you need that 100mpg diesel KLR!


The diesel would be nice, but the price as I am sure you know is a bit high. The reason I want additional range is for adventure touring. The KLR gets around 50mpg when cruising, but real world mixed surface riding with aftermarket exhaust and jetting does worse. Bottom line is I want as much range as can reasonably be had, one less thing to worry about....


dude, even at 40 mpg, thats 240 miles before you hit reserve.....every ass and leags need a good streatch and walk around after 250 miles.....even if it is just to get gas.

That's assuming there is gas to get....


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