Author Topic: 5.5 mm fuel line  (Read 847 times)

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Offline bryanj

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Re: 5.5 mm fuel line
« Reply #25 on: October 18, 2025, 10:26:44 AM »
I do the same Mark but gently tap in a centre punch first to take out the "shrinkage" from original fit
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Offline HondaMan

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Re: 5.5 mm fuel line
« Reply #26 on: October 18, 2025, 10:35:06 AM »
I do the same Mark but gently tap in a centre punch first to take out the "shrinkage" from original fit

That's a smarter idea! I think I'll try that on my old one. :D
See SOHC4shop.com for info about the gadgets I make for these bikes.

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Offline jlh3rd

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Re: 5.5 mm fuel line
« Reply #27 on: October 20, 2025, 05:16:24 AM »
The last bulk 5.5mm fuel line I got from Honda seemed to have a larger O.D. than the original.
Yep, it is: it also has a dull red stripe on it, which Honda said indicates it is 'ethanol-compliant' (?) hose. It's OD is about 1mm bigger than the old 1970s stuff, but still manages to fit through the holes in the carb racks OK.

FWIW

original mid 70's fuel line and overflow lines were like a dark ash grey (almost black) with a continuous red stripe. Individual lines were available back then, color code "4". No part # for bulk purchase. It appears that style disappeared around the late 70's, and became bulk purchase only.
Current bulk Honda , at least as shown by CMS, is black with red lettering...or just black from other sources it seems., color code "6".
Color chart on CMS, my original Honda parts book doesn't have that, but the lines on my '75 have the red stripe.
Was there ethanol fuel in the 70's ?

« Last Edit: October 20, 2025, 05:18:10 AM by jlh3rd »

Offline denward17

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Re: 5.5 mm fuel line
« Reply #28 on: October 20, 2025, 06:03:46 AM »
The last bulk 5.5mm fuel line I got from Honda seemed to have a larger O.D. than the original.
Yep, it is: it also has a dull red stripe on it, which Honda said indicates it is 'ethanol-compliant' (?) hose. It's OD is about 1mm bigger than the old 1970s stuff, but still manages to fit through the holes in the carb racks OK.

FWIW

original mid 70's fuel line and overflow lines were like a dark ash grey (almost black) with a continuous red stripe. Individual lines were available back then, color code "4". No part # for bulk purchase. It appears that style disappeared around the late 70's, and became bulk purchase only.
Current bulk Honda , at least as shown by CMS, is black with red lettering...or just black from other sources it seems., color code "6".
Color chart on CMS, my original Honda parts book doesn't have that, but the lines on my '75 have the red stripe.
Was there ethanol fuel in the 70's ?

Probably different in each state, but IIR, it was late 90's in NC.

Offline jlh3rd

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Re: 5.5 mm fuel line
« Reply #29 on: October 20, 2025, 09:08:37 AM »
yeah, In Louisiana, all I remember seeing was the phase out of lead.

Offline Don R

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Re: 5.5 mm fuel line
« Reply #30 on: October 20, 2025, 09:26:26 AM »
  I'm just wondering if anyone got smarter since the removal of lead from the fuel? I seem to remember that was the reason. Sorry, off topic. 
  I'll open the fuel line today and check for markings, OD, stripes and color.
No matter how many times you paint over a shadow, it's still there.
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Offline Don R

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Re: 5.5 mm fuel line
« Reply #31 on: October 20, 2025, 06:49:34 PM »
  Here is the hose, I guess it's Tariff phobia that got me to spend $86 on fuel line. The OD matches the spring clamps, there is no stripe except the gray lettering. OCP parts warehouse.
« Last Edit: October 20, 2025, 06:57:23 PM by Don R »
No matter how many times you paint over a shadow, it's still there.
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 You don't need a weatherman to know which way the wind blows.

Offline BenelliSEI

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Re: 5.5 mm fuel line
« Reply #32 on: October 23, 2025, 11:17:49 AM »
Don….. I bought the same stuff and well worth it!

Offline HondaMan

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Re: 5.5 mm fuel line
« Reply #33 on: October 23, 2025, 11:33:49 AM »
Interesting!
I have a [last piece] chunk in a Honda bag of the 5.5mm size that has the red stripe, but the 3 newer bags (within the last 4 years) all just have the lettering in them. With all this talk, I had to go look. :)
The 3.5mm hose I have is similar: one last piece from long ago (not long enough for a carb bowl overflow) has the stripe, the newer hose is also lettered.
See SOHC4shop.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book
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Link to website: https://sohc4shop.com/  (Note: no longer at www.SOHC4shop.com, moved off WWW. in 2024).

Offline HondaMan

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Re: 5.5 mm fuel line
« Reply #34 on: October 23, 2025, 11:42:09 AM »
Was there ethanol fuel in the 70's ?
Here in Colorado it appeared in 1981 with great accolades of saving the world. It replaced the Premium pump then in most gas stations. We had 3 grades before that: Premium, mid-grade and Regular. When lead vanished it went back to the 3-grade-pumps again, all unleaded. When MTBE showed up it was in all 3 grades (1988 here, I think it was) until about 2009 here. The MTBE was much hated here because it ruined the fuel tanks in most gas stations (notwithstanding what it did to our cars) and damaged a lot of wildlife, mostly birds.

It also turned the rubber hoses on the bikes into plastic, losing all flex and eventually cracking at the brass slip-on fittings and nipples. Honda touted the "new Red" stripe on their fuel lines then, saying it wouldn't shrink with ethanol - but with MTBE it still did.
See SOHC4shop.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book
Link to My CB500/CB550 Book: https://www.lulu.com/search?sortBy=RELEVANCE&page=1&q=my+cb550+book&pageSize=10&adult_audience_rating=00
Link to website: https://sohc4shop.com/  (Note: no longer at www.SOHC4shop.com, moved off WWW. in 2024).

Offline Don R

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Re: 5.5 mm fuel line
« Reply #35 on: October 23, 2025, 12:40:38 PM »
 The gas station tank damage might explain why I (a House plumber/sometimes pipe fitter) was recruited to re-pipe a gas station that got new tanks. It seemed the usual gas station install guys were swamped with work and couldn't man the job aside from pulling the old tanks and dropping in the new ones.
 It was quite an experience when a groundwater/ground fuel culvert pipe needed cutting with a torch. I told my boss no for the first time. After we got the fire department there and they sprayed a compound into the soil/fuel/water they suited up, charged a line and told me to go ahead. I donned my best welding gear and didn't blow myself up or set fire to anything.
No matter how many times you paint over a shadow, it's still there.
 CEO at the no kill motorcycle shop.
 You don't need a weatherman to know which way the wind blows.

Offline seanbarney41

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Re: 5.5 mm fuel line
« Reply #36 on: October 23, 2025, 07:21:09 PM »
I remember hearing about "Gasohol" back in the 70s/80s.  Can also remember seeing stickers on gas pumps stating "guaranteed less than 5 percent alcohol content" at least as far back as 1987.  That was when I got my drivers license in Michigan.
If it works good, it looks good...

Offline scottly

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Re: 5.5 mm fuel line
« Reply #37 on: October 23, 2025, 07:31:11 PM »
I remember Gasohol from 1980 in the bay area of CA; IIRC, it was a cheaper option, with the price of gas going up after the situation with the hostages in Iran caused a second "gas crisis". I don't think I saw it anywhere else in CA, and it seemed to be short-lived.
I don't recall ever having problems with MTBE, other than the gas smelled a bit different when re-filling? 
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Offline jlh3rd

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Re: 5.5 mm fuel line
« Reply #38 on: October 24, 2025, 04:42:48 AM »
FWIW.....useful (less) trivia. 🫤



Decades ago, I stumbled across an article pertaining to factory original bikes in which the article stated that 70s' Hondas came with fuel lines and carb drain lines that had a red stripe. So I grabbed a flashlight and checked my bike and sure enough that's what was on it. It was before I really began seriously digging into (or caring about) factory original equipment. I didn't keep the article.....and I can't find it.
At the old honda shop I frequent this became a topic and we found an OEM,NOS red stripe fuel line, order dated 1973. This is the earliest we've found. This is before gasohol, or whatever. The latest time period the owner thinks this became NLA was the late 70's., as honda  went to bulk fuel line sales , not individual pieces. His memory.
He has bulk Honda fuel line but has no bulk red striped line and thinks he would have if it had been sold as such.
CMS shows ash grey/ red stripe for the  500's/550's up to 1978....as far as they go. I didn't check other models.
Not conclusive of course.
I have found aftermarket lighter grey with a red stripe but the stripe is not continuous. (JT Marks?) (4 into1?)

If there is an official honda document stating the reason for the red stripe I'd really like to have it.

This is just a trivia thing for the few of us who like original unrestored data.