Bimota Forum

[Lozza212]

Hi All,
I have mistakenly put E10 petrol into my Mantra Fuel Tank instead of 91. ( or better )
The problem is the bike sat around for a month un-ridden and the fuel turned all brownish/yellow and it looks like it has attacked the inside of the tank.
I have drain the tank immediately and drained the carbs as well.
Now for my questions:
Does anyone know what the tank material is - plastic or fibreglass.
Has anyone had this issue before and what did you do to clean out the tank and neutralise the effects of the E10.
Thanks in advance,
Laurie
Melbourne.
Australia

[Jonny B Bad]

The tank is most likely made of nylon. The ethanol in E10 is hygroscopic, that is to say it absorbs moisture from the atmosphere - like Dot 4 brake fluid. Eventually the water will separate out of the fuel and settle at the bottom of the tank, as it is heavier than the petrol. That water is acidic and will dissolve any deposits/coating inside the tank. The nylon will absorb water, up to 3% of its mass and will swell, which may move tank fixings out of alignment. The swelling should subside as the nylon dries out.

In theory, it’s possible to coat the inside of the tank, to prevent further moisture absorption. But this is messy and prone to failing, clogging up fuel tap screens and filters with bits of coating. Better is to try to use only “super” grade fuel with no more than 5% ethanol, combined with an additive that prevents the phase separation of any water from the fuel.

Having drained the tank, you should be able to just re-fill with E5, complimented with something like Frost’s Ethomix or similar.

Good luck!
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What, Jonny's gone!