Fuel hose

[mikenixon]

Some have asked why I don't fit new fuel hose to the carburetors I rebuild. There are reasons. But the situation is not a simple one so allow me to explain.

Fuel hose for motorcycles is one of the harder things to deal with when rebuilding carburetors. There just isn't an easy way to handle it. Here are some of the problems. First, very few fuel hose choices are sized correctly. All of Honda's fuel fittings are metric, and 90 percent of the available fuel hose is Imperial. This may seem a minor issue, but it really isn't. There is a pretty big difference between 5mm and 1/4", for example.

Next, Honda often annoyingly puts differently-sized fuel fittings on a given carburetor/petcock combination, meaning that one end of the hose has to fit one size while the opposite end of the same hose on the same bike is forced to stretch to a larger size. Strange, this, but there it is. And quality fuel hose that can fit properly on two different fuel fittings is not real common.

Third, quality. 1970s-era Hondas came from the factory with dual-layer fuel hose. Incredibly good stuff. The outer layer was hypalon, the same thing that covers spark plug wire. The inner was Viton, very high quality. This dual layer hose was so good it resisted decay for over 30 years, what with the outer layer standing up to the ravages of ultraviolet/ozone/etc. many times better than any other hose. So good in fact that I would rather leave still-intact but somewhat-hardened OEM fuel hose on the carbs rather than replace it with anything else I can find. Because that "anything" is going to inevitably be inferior hose. 1

Fourth, though Honda still makes "factory" hose available, it is not this original stuff, but rather a third party substitute. It's fair hose, but not the same as that used in the 1970s and into early 1980s. Interestingly, a certain Japanese importer *does* offer the original Honda red-stripe dual-layer hose. 2 So the equivalent hose is available, just not from Honda. But it is breathtakingly expensive. So, just put the Honda red-stripe hose on, problem solved. Well, that would be fine except the cost is prohibitive for me to include it in the rebuild, and few customers will pay the extra freight for this good hose. And there are other issues. 3 I haven't sold any red-stripe hose in years.

Fifth, quality, again. Motion Pro's best hose is thin-wall, kink-prone, and tending toward hardening. The Geman-made Continental brand braided outer layer stuff, once found on early BMW motorcycles, though it looks rugged, is also very poor quality. Underneath the handsome braiding is near natural rubber hose that softens dramatically as it ages. K&L's Tygon (i.e., plastic) is that famously bad stuff that hardens like a rock-- remember pushrod Brit bikes? And what about auto parts store hose? Except in the 1/4" size, which occasionally can be purchased in a form snug enough to substitue for Honda's 5.5mm original, most auto parts and hardware store stuff is pretty far off size-wise and worse, much of it chunks internally, resulting in debris in the fuel system. One thing I will say for most car hose though, one thing in its favor, at least it is designed to resist kinking, which almost none of the stuff from motorcycle sources can claim.

Sixth and last, and perhaps the hurdle that remains even after the other issues are solved, is this. With various petcock and carb and fuel filter combinations and configurations possible, I have found it is best to let the customer make his own fuel hose arrangements. If I try to anticipate things, all I am doing is wasting product because lengths and curve radii and clamping method and inline filter choices, due to individual bike setup-- are all variables. It's best if I stay out of it, though occasionally I will ship carbs with a piece of hose for the customer to fit as he chooses.

So there you have it. The challenges of supplying my customers with new fuel hose. The choices run the quality gamut. The customer's expectations and configurations vary widely also. And the marketplace is geared toward cheap. And I don't do cheap.

1 Obviously, not if it is already so hardened it will leak. All carb rebuilds are leak-tested.

2 Kawasaki also used this company's dual-layer hose, but their's was marked with a blue stripe instead of a red one.

3 For some strange reason, only the 5.5mm size fits properly. The company's larger 7mm hose for later Honda carbs is quite a bit off.

[77Gowing]

Mike,
You mentioned infrared with regard to fuel line hose. Forgive my suggestion...but don't you mean ultraviolate light damage? Here in West Texas, where most vehicles come in either white or silver due to the harsh sun, it's the UV light that can ruin a vehicle right quick.

BTW, why not consider selling bulk metric hose, and let us route, clamp & fit our own to our bikes? I'd buy. I ran into the hose problem on my 77.
My first set of fuel hoses were juuuust barely long enough, that I was afraid they'd pull off. Later, I paid dearly for some bulk, but forget where I got it from. Now I dont worry and have forgotten the price pain.

[mikenixon]

Mike,
You mentioned infrared with regard to fuel line hose. Forgive my suggestion...but don't you mean ultraviolate light damage? Here in West Texas, where most vehicles come in either white or silver due to the harsh sun, it's the UV light that can ruin a vehicle right quick.

BTW, why not consider selling bulk metric hose, and let us route, clamp & fit our own to our bikes? I'd buy. I ran into the hose problem on my 77.
My first set of fuel hoses were juuuust barely long enough, that I was afraid they'd pull off. Later, I paid dearly for some bulk, but forget where I got it from. Now I dont worry and have forgotten the price pain.

Hey, 77-- Yes, ultraviolet. I knew there was something wrong with that sentence...

[Chris in TN]

If you look up the Honda part # 95001-55008-60M for 5.5 mm bulk hose it'll cost you about $85 from an online Honda motorcycle parts retailer. The same part number ordered from an online Honda car parts dealer will run about $45.

[mikenixon]

If you look up the Honda part # 95001-55008-60M for 5.5 mm bulk hose it'll cost you about $85 from an online Honda motorcycle parts retailer. The same part number ordered from an online Honda car parts dealer will run about $45.

Yes, but it's not the same hose that came on Honda carbs in the 70s and early 80s. It's not bad hose, and I use it occasionally on various projects, but it's not the same as the original and it's not much better than aftermarket hose, comparatively. Below is the original dual-layer premium hose that is available only through K&L now, the stuff that lasted 30+ years. Ignore the URL, I gave up that domain a long time ago.

[mikenixon]

It's not widely understood, but Honda has dumbed-down much of their vintage parts. They are to be commended for at least addressing vintage, because most of the Big Four do not. But the upshot is Honda is mostly doing so using third-party suppliers, which results in at minimum disappointing parts quality and at times really unacceptable parts, such as weaker cam chains and similar parts.

[mikenixon]

If you look up the Honda part # 95001-55008-60M for 5.5 mm bulk hose it'll cost you about $85 from an online Honda motorcycle parts retailer. The same part number ordered from an online Honda car parts dealer will run about $45.

Didn't know about that disparity. Unfortunately, what Honda sells now is not the same hose that came on Honda carbs in the 70s and early 80s. It's not bad hose, and I use it occasionally on various projects, but it's not the same as the original and it's not much better than aftermarket hose, comparatively. Below is the original dual-layer premium hose that is available only through K&L now, the stuff that lasted 30+ years. Ignore the URL, I gave up that domain a long time ago.

[desertrefugee]

Oh my gosh does this explain a lot. I have run into these disparate size requirements on multiple Hondas. I thought it was just me. Admittedly self-induced, but on my GL1000 where I fitted a 1200 electric fuel pump, the problem was so bad I employed the use of a reducer in the line between the fuel pump and the carburetor bank!

I gotta say Mike, you have a knack for sometimes bringing even the more mundane issues to life with amazing clarity and revealing subtle, yet annoying artifacts of working on these vintage machines. Sheesh. Fuel line fer crying' out loud!

[Chris in TN]

If you look up the Honda part # 95001-55008-60M for 5.5 mm bulk hose it'll cost you about $85 from an online Honda motorcycle parts retailer. The same part number ordered from an online Honda car parts dealer will run about $45.

Yes, but it's not the same hose that came on Honda carbs in the 70s and early 80s.

I know it's not the same hose as years ago. What I was pointing out is that you can get hose that fits and get it cheaper from the car parts guys.

Here's why that matters for many of us. If I go to the local Honda dealer and order hose the guys behind the parts counter will try to hand me US 1/4" hose and swear it's the same as the Honda stuff. How do I know this? Because that's exactly what happened at Honda Yamaha Of Knoxville 5-6 years ago and when I protested that 1/4" was the wrong size he insisted that it didn't make any difference. Now, let's assume you get a better guy behind the parts counter at YOUR Honda shop and he genuinely wants to give you the right size hose. That's good for sure but he'll want stupid money for it. So, what I was trying to point out is that you can get the same Honda part # for 5.5 mm hose at nearly half price from a internet Honda Auto parts seller. That's all.

[mikenixon]

Appreciate it. The hose I was calling breathtaking expensive is the one I am focusing on at the moment, the 70s stuff. Do appreciate your comment though. Good to know the 90s hose is available at a bargain.

[mikenixon]

Oh my gosh does this explain a lot. I have run into these disparate size requirements on multiple Hondas. I thought it was just me. Admittedly self-induced, but on my GL1000 where I fitted a 1200 electric fuel pump, the problem was so bad I employed the use of a reducer in the line between the fuel pump and the carburetor bank!

I gotta say Mike, you have a knack for sometimes bringing even the more mundane issues to life with amazing clarity and revealing subtle, yet annoying artifacts of working on these vintage machines. Sheesh. Fuel line fer crying' out loud!

As you can see, including hose on my rebuilds actually adds a layer to my work beyond mere carb rebuilding... You said it, fuel line after all...

[Lucien Harpress]

I ran into a similar issue with my CT90 K0. The petcock is integrated into the carb, with two fuel lines running out of the tank, though a small hole in the frame, and into two inlets on the carb RIGHT next to each other. A local Honda dealer had the "stock" 5.5mm line (I believe), but the outer diameter was definitely larger, so much that I almost wasn't able to get both fitted to the petcock. It's definitely one of those things that's more trouble than it needs to be.