17 August 2021

Ask an expert: how to prevent your fuel tank from rusting

In this edition of Ask An Expert, we sought to find the answer to a question a reader left us on our tank refurbishment article. 

"I have a Honda 70 ADV that had a rusty tank, it looks like I've done a good job with the rust using full nuts and a full tank of white vinegar. What I want to know is if it has a full tank of petrol will this prevent rusting again or would you advise on a sealer?"

We spoke to Steve Cooper, Editor for the Vintage Japanese Motorcycle Club and he explains various solutions below. 

Modern fuel containing ethanol can and will promote corrosion over time regardless of brand.  

  • Tank liners will prevent corrosion but may, at a future date, fail in the presence of fuels containing ever-increasing levels of ethanol and other additives. Some are more resistant to modern fuel than others so check if a selected liner has actually been evaluated with UK fuel. Ultimately tank liners are probably best considered as 'fallbacks' if a tank has a weeping seam, has become thin or is pin holed etc. 
  • If a bike is not being used for months on end the best solution is to drain the fuel out and spray the inside with a quick shot of aerosol lubricant cum light oil. 
  • Alternatively, there are numerous brands of 'fuel stabilisers' on the market expressly designed to stop fuel degrading and becoming corrosive. It wouldn't be right to single out any one brand -it's better to speak to fellow enthusiasts who have used similar products.   

According to Steve, the petrol companies are not really interested in old bikes and their products are designed for modern vehicles with fuel injection and high-end engine management systems. 

Fresh fuel has been a hot topic for Ask An Expert in recent months. For further advice, take a look at our blog, Ask An Expert: Should I Fill My Tank With Fuel When I Store It? 

If you have a classic question you would like answering by an expert, simply complete our Ask An Expert form and we could be answering your question next week. 

The information contained in this blog post is based on sources that we believe are reliable and should be understood as general information only. It is not intended to be taken as advice with respect to any specific or individual situation and cannot be relied upon as such.