Motoscrubs.com

This is "wake-up call" just in case others haven't checked there fuel hoses in a wee while, or are not sure of what they are made.

The two images show what I found beneath the tank of my Yamaha SRX600 Mono, when checking before filling the tank with fuel and in the light of the UK moving to 10% Ethanol fuel in September this year (2021). The fuel hose is a 'standard' nitrile one that has been fitted for 3 years and sits above the engine and carburettors in a confined space, so it gets a lot of hot/cold cycling. Braided cloth hoses are usually nitrile hoses with a nylon braid cover.

You can see the "irrigation" cracks and imagine their effect of leaking fuel directly above the cylinder head and beneath the fuel tank. A bomb in your crutch!

Viton™ fluoroelastomer, whilst costing approximately 10 times as much as nitrile hose is apparently more resistant to oxidisation and the chemical effects of ethanol, so, another little job to do on the fleet. Check all the fuel lines and overflows!

Nitrile_vs_Viton™

This is but one of many explanations online.

Good health, Bill

Aye Bill, I had already come across this on my modern Ducati which has the fuel pump inside the tank. Last Summer it conked out on the way home from a ride and after being rescued, I found that the rubber fuel pipe in the tank had swollen and come off of the metal pipe. The rubber pipe (marked 'fuel pipe') was like jelly. I did a search and found some supposedly ethanol resistant pipe, but time will tell. This is just the beginning.

Gates Corrp. makes very good fuel hoses. The best ist "Gates Submersible Fuel Line Hose" (4219) https://www.gatestechzone.com/en/product-info/passenger-cars-and-light-commercial-vehicles/hoses/fuel-hoses. It is made of FKM (ISO, EN etc. standard name). Viton is the same stuff, but a brand name of DuPont Chemicals. Other manufacturers use differnet names, so search for FKM oder FPM.

Hans

There doesn't seem to be many properly Ethanol compatible (certainly not traditional looking) fuel hoses available and many are described as "tolerant". We did find some from Ariete that we stock but it is only available in opaque black or "lurid" green. It is double walled and glossy in appearance on the outside. None of the transparent hoses they make are marketed as compatible with ethanol.

Nigel

Maybe we should go back to the old solution of using metal pipes for fuel.

The best fuel line I have found is the Motion Pro fuel line available in 1/4 and 5/16 at many shops handling dirt bikes, or on Amazon. It’s made of what Motion Pro calls Tygon. It’s more or less the same stuff as comes on modern dirt bikes. It doesn’t harden, crack, or get hardened with age. It works quite well. The only shortcoming I see is it’s gray color.

The best fuel line I have found is the Motion Pro fuel line available in 1/4 and 5/16 at many shops handling dirt bikes, or on Amazon. It’s made of what Motion Pro calls Tygon. It’s more or less the same stuff as comes on modern dirt bikes. It doesn’t harden, crack, or get hardened with age. It works quite well. The only shortcoming I see is it’s gray color.

"Tygon" is a trademark of Saint-Gobain Company https://en.wikipedia.org/wiki/Tygon_tubing. Wikipedia tells us, that they produce many types of pipes, for different use cases. These two seem to satisfy our needs:
https://www.processsystems.saint-gobain.com/products/tygon-lp-1100-flexible-fuel-tubing
https://www.processsystems.saint-gobain.com/products/tygon-f-4040-lubricant-fuel-tubing

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