C C ... I don't think the tank will shrink back , but maybe emptying it and letting it completely dry out may help !? I thought of applying a light vacuum to it after it is totally dry (small vac. pump like we mech.'s use for testing things .) with it sitting in the sun , but that may distort it in other ways ...

Glenn

Mine shrinks when I wash it in Cold Water !!!!!!!!!!!

Oh, you mean the Sherco fuel tank, Charlie? Yea, well I had indeed posted on the Sherco threads how mine on the "07 had indeed shrunk back after going back to pure alcohol free Avgas.

Took a while I suppose, was not really testing for that at the time, it just happened.

I am sure al this has to do with the permeability of the material and molecular science, and not sure if one is better off draining and venting or purging out with other stuff.

Ck with Tony27 on the Sherco threads to see how it went with the tank he replaced, possibly.

Running avgas in the new tank with no return of tank growth, haven't tried the old tank back in the frame since it's been sitting empty after replacement

The more I think about sherco tanks which are probably made by acerbis the more I come back to nylon's attraction of water, when I was still working as a toolmaker it was well known just how much nylon grew through moisture absorbtion esp in the first 24hrs after moulding. The ethanol has a water base/attracts water which is probably the nylon tanks swelling over time

Here is a site to find non-ethanol gas in your area - www.pure-gas.org

Retro

My first trials bike was a Scorpa. I didn't have any fuel related problems with the tank. I sold that bike and ride Betas now. Last year i found a product called StarTron. It is an enzyme additive which neutralizes the alcohol and water in ethanal. I don't need to use it in my bikes because i have found a fuel station nearby which sells unleaded premium with no ethanol mixed in, but use it in my vehicles. It seems to work as described as my toyota truck now runs smoother and after a year of using it gets a 3MPG improvement. I have seen different concentrations of the pork chop shaped bottle, but the bottle that i found has 8 ounces and treats 128 gallons. A little goes a long way. I think this product might solve the problem of the ethanol attacking the plastic tank.

http://mystarbrite.c...00/136/lang,en/

http://mystarbrite.c...15/202/lang,en/

http://mystarbrite.c.../4/208/lang,en/

http://mystarbrite.c.../14/37/lang,en/

Edited July 26, 201313 yr by liviob

I keep star tron in my lawnmower and weed eater too . My vehicles all run ethanol free premium , but for the mower and such Star tron works as advertised for sure ... good stuff

Update...after a few tankfuls of aviation fuel, my tank has returned to its original size.

Great! problem solved.

I also noticed that tightening the swollen tank down stressed/deformed it enough to cause a leak between the petcock and tank.