Tygon fuel hose

[Toecutter]

Went to go for a blatt today and the bike started fine. Whilst warming up started running progressively worse eventually dying completely. Had a little nose around and noticed the Tygon fuel hose had collapsed on itself, sticking the wall of the tube together sealing itself completely shut. Very strange. It’s a if the heat from the engine, during cooling down had created a vacuum through the fuel system collapsing the hose. 
 

Pulled the hose off and poked a dipstick down it to separate then immediately stuck itself back together again. Always run E5 fuel. The hose is fairly old to be fair so I’ll order some fresh.

little odd though.
 

pic’s probably not that great.

[Gixer1460]

I don't think any fuel pipe these days is immune to attack from 'E' rated fuels! Best to treat whatever you use as a service interval item and replace it annually or at worse bi-yearly! Modern EFI stuff all uses that hard plastic which seems to cope although I bet that becomes embrittled after a few years!

[wraith]

I just replaced my fuel lines over winter each year. Because as @Gixer1460says don't matter how good the fuel line says it is they all fail with modern fuels. 

Lost count the amount of times I've gone to go for a ride just to find ever when I start the bike or half way through the ride, the fuel line splits  

[Enjoythesilence]

Agree with the shit fuel wrecking stuff, and while were at it give me my lead back and 2 and 3 star

[Fazz711]

1 hour ago, Enjoythesilence said:

Agree with the shit fuel wrecking stuff, and while were at it give me my lead back and 2 and 3 star

What no 5*

[Gixer1460]

31 minutes ago, Fazz711 said:

What no 5*

LOL's - unless you run a turbo, ain't needed . . . . . . for us at least unless you've got an 'E Type' for giggles! 

[Dezza]

I would suggest that the simplest explanation of the original problem is the wrong grade Tygon hose is being used. They make a whole load of different grades for different fluid applications so it's easy to accidentally buy the wrong grade. Personally, I have over the last 40+ years had absolutely no problem with any fuel hose degrading to the degree shown in the OP. I now use cloth braided stuff, like you see on old British bikes. You can get rubber end plugs for the 8mm equivalent for a neat finish with spring clips.

Jap bikes have been designed for unleaded fuel since at least the late 1960s. When unleaded came in during the mid-80s in the UK, the recommendation was to use it in preference to leaded fuel. The lead was only there so motor manfacturers could cut production costs by using cheatskate materials for valve seats. It is highly toxic so good riddance to lead in fuel. We have lived with lead-free fuel now for nigh on 40 years so I just don't understand why anyone wants it back. If you have an engine that needs mega-high octane fuel, then it's probably a classic Yamaha TZ or RG track bike (lucky you!) so use avgas.

Removing lead from fuel is not the same as adding ethanol. The two seem to be conflated by many. I for one do not understand this 'logic'. It's there for a reason and we all know the potential unwanted effects. Drain your fuel system when your machine is left standing for any length of time. Use Esso super if you don't want ethanol, but you will still get problems if its left in a fuel system with fine drillings, i.e. carbs. My guess this is because there are no longer added chemicals to prolong the shelf life of the fuel. Again, their removal is not the same as adding ethanol.

We all just have to live with what fuel we can get and will have to do this more in the future and be proficient at avoiding the worst effects in older bikes. Fuel without ethanol is still available if you don't want ethanol though. I sometimes wonder if the flat cap/green overalls/steel toecaps brigade at summer steam rallies all sit around moaning that they can't get high-grade south Wales coal anymore for their road locomotives. Or if they just get on with it and use what they have available, and faff about with their impressive machines accordingly. We will soon be the two-wheeled equivalents. Rant over .

Edited June 16, 2025 by Dezza

[Guest]

I use genuine Suzuki pipe. It's a bit expensive, but once on lasts....well, I don't know, I've had some on for 10 years or so, it's still fine. It came in a 600mm length or something, and has done several bikes

I don't get any particular issues with modern fuel that I didn't get in the 80s and 90s. Put Petrol in, ride the bike, works fine. Don't leave it standing for months. Easy.

[Duckndive]

23 hours ago, Toecutter said:

 The hose is fairly old to be fair so I’ll order some fresh.

Lots of fake stuff around 

Just make sure you get it from a reputable source ....

[arnout]

4 hours ago, Duckndive said:

Lots of fake stuff around 

Yup.. Once I was given some length of "Tygon" tubing that turned very sticky after a year or so. After cleaning it would keep bleeding chemicals that were probably meant to keep the hose as flexible as the real F-4040-A stuff.
Still F-4040-A hose will deteriorate after a number of years, but exposure to ethanol speeds this up shrinkage and hardening a lot. Other types/grades of Tygon hose are far better suited to use with fuels with ethanol, like LP-1100 and LP-1200, but aren't as super flexible as F-4040-A.

After I failed to find a trustworthy source to purchase only a short length of F-4040-A I started looking for alternatives. Double skinned hose Ariete 1958/A/10-S was relatively cheap and promised ethanol and UV resistance, and so far (a few years now) the stuff hasn't shrunk or hardened (yet).  I do however take care to avoid filling up with anything other than E5 (oftewel Euro 98 Super Plus), so haven't really tested the ethanol resistance.
Downside of this 1958/A/10-S stuff is that sadly it isn't as supple as Tygon F-4040-A. Also has an ugly purple-ish colour, but is more transparent than the yellow Tygon hose.

[slayer61]

I've had great luck with Motion Pro fuel lines. They're readily available on my side of the pond 

[Toecutter]

Cheers for the response. Ordered a section of tygon 4040-A. Fitted and went for an hour or so blatt. All good, this was on saturday. Diddnt use the bike all weekend, forgot all about the hose with regards to checking until this morning. 

Same thing had happened, walls collapsed but not stuck together thankfully. Turned the fuel tap on, which is a pingle and luckily the hose found its shape again. Wierdly, the t-piece also has tygon hose purchased and fitted at the same time as the upper from the same length, which has held its shape fine. 

Think I'll bin it off for fuel injection hose...

[BigT]

On 6/16/2025 at 6:47 AM, gs7_11 said:

I use genuine Suzuki pipe. It's a bit expensive, but once on lasts....well, I don't know, I've had some on for 10 years or so, it's still fine. It came in a 600mm length or something, and has done several bikes

I don't get any particular issues with modern fuel that I didn't get in the 80s and 90s. Put Petrol in, ride the bike, works fine. Don't leave it standing for months. Easy.

+1 on OEM hose

We've had E10 for over a decade and the hose is still good 

[Rossco(Iceman Josros)]

On 6/16/2025 at 11:35 AM, Dezza said:

I would suggest that the simplest explanation of the original problem is the wrong grade Tygon hose is being used. They make a whole load of different grades for different fluid applications so it's easy to accidentally buy the wrong grade. Personally, I have over the last 40+ years had absolutely no problem with any fuel hose degrading to the degree shown in the OP. I now use cloth braided stuff, like you see on old British bikes. You can get rubber end plugs for the 8mm equivalent for a neat finish with spring clips.

Jap bikes have been designed for unleaded fuel since at least the late 1960s. When unleaded came in during the mid-80s in the UK, the recommendation was to use it in preference to leaded fuel. The lead was only there so motor manfacturers could cut production costs by using cheatskate materials for valve seats. It is highly toxic so good riddance to lead in fuel. We have lived with lead-free fuel now for nigh on 40 years so I just don't understand why anyone wants it back. If you have an engine that needs mega-high octane fuel, then it's probably a classic Yamaha TZ or RG track bike (lucky you!) so use avgas.

Removing lead from fuel is not the same as adding ethanol. The two seem to be conflated by many. I for one do not understand this 'logic'. It's there for a reason and we all know the potential unwanted effects. Drain your fuel system when your machine is left standing for any length of time. Use Esso super if you don't want ethanol, but you will still get problems if its left in a fuel system with fine drillings, i.e. carbs. My guess this is because there are no longer added chemicals to prolong the shelf life of the fuel. Again, their removal is not the same as adding ethanol.

We all just have to live with what fuel we can get and will have to do this more in the future and be proficient at avoiding the worst effects in older bikes. Fuel without ethanol is still available if you don't want ethanol though. I sometimes wonder if the flat cap/green overalls/steel toecaps brigade at summer steam rallies all sit around moaning that they can't get high-grade south Wales coal anymore for their road locomotives. Or if they just get on with it and use what they have available, and faff about with their impressive machines accordingly. We will soon be the two-wheeled equivalents. Rant over .

We’ll put@Dezza 

as for Tygon I use it but never got on with it 100% as it is quite flimsy and kinks easily and so I quite often end up using a Suzuki oem type hose I buy off fleecy bay 

[wraith]

I use this stuff 

Being reinforced it doesn't kink.

I change my lines each winter but each time I've removed the pipe it looks in good condition. So this year I'm not going to change it and see how it goes.

The only downside is it's thicker than standard pipe being reinforced 

[Gixer1460]

2 hours ago, wraith said:

The only downside is it's thicker than standard pipe being reinforced 

That's the thing that puts me off - fuel inlets on RS carbs are bloody tight even with 'regular' pipe then plus a clip - hmmm!

[Toecutter]

I ended up using rubber pipe with over braid in the end. 

The tygon hose had swollen a week later causing leakage at the tap outlet... Turd.

Much better now, although a little bulkier...

 

[wraith]

The only other way I found using thin wall pipe, is to put a spring over the hole pipe to stop it from kinking