Fuel line size?

[mattsz]

Hey guys - I'm in a pissing contest with an ebay supplier about fuel line size.  I read on one of these SOHC forums that 5.5mm is the correct size fuel line for my '77 CB400F, so that's what I ordered.  It arrived, with a much larger OD than what's on my bike, which I am told is original.  So the clamps won't fit.  Of course, now I can't find the info on either forum...

In communicating with the seller, he's claiming to know the measurement of my bike's petcock outlet and that I should have ordered 4.5mm fuel line.  The ID of the old line and his new one look the same to me, but the old one is probably stretched out a bit...

Since most OEM parts sellers offer part numbers but no dimensions, and I've seen conflicting info on other parts sites... exactly what part of the petcock outlet tube do you measure, and how does fuel line size relate to that measurement?

[mattsz]

Keep in mind, the 77 USA model seems to be a one-off in so many respects...

[Bryanj]

You need 5.5mm id fuel line BUT not all makes have the same OD  and 5.5 is a tight enough fit that the clamps are not needed, that is if he has supplied 5.5 and not 1/4 inch which is too big!!

[mattsz]

I measured the ID of the hose he sent.  It's difficult, because it's soft, and it came off a roll so it's curved and the ID isn't perfectly round - but it really seems like it's 5.5mm, and when I increase my caliper to 1/4", it definitely doesn't fit - I can just span the 1/4" gap of the jaws if I squeeze the hose flat.  He offers it as "Genuine Honda" fuel line - it's got lots of writing on it, but nothing that says "Honda" or anything that resembles the part number he's listed (95001-55008-60M).  A side-by-side photo, showing the two hoses and the clamp which definitely won't fit the new hose...

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Here's what he said: 

OK, found your problem. I took a 5.5mm petcock and the large part of the nipple is 6.95mm the petcock for your bike measure 6mm so you have a 1mm difference which looks like your hose is suppose to be 4.5mm which your clamps will work on.

Measuring my original petcock, the large part of the nipple is indeed 6mm (well, 5.95) and the narrow section between the nipple and the petcock body is 5mm.  The hose does grip the nipple, but it slides on and off pretty easily.  Although it looks right, there's no guarantees the petcock is OEM Honda, though, either...

Do you know what size the outlet pipe should be in relation to the hose diameter?

[Bryanj]

The 5.5 viton hose i bought in UK is a tight fit on the carb and petcock nipples. Tell me how long you need and i will post you some at cost, i also have a box of various size clipes so would put those in as well

[mattsz]

The 5.5 viton hose i bought in UK is a tight fit on the carb and petcock nipples. Tell me how long you need and i will post you some at cost, i also have a box of various size clipes so would put those in as well

That's kind of you Bryan - but I assume posting such to the USA would be prohibitively expensive?  Surely if I can educate myself as to what size works for my petcock (and carb, I guess) I should be able to find what I need over here...

The stuff I just bought is 5.5mm ID - so I could figure out how to use it one way or the other.  Whether that's the right size is in question...

[Bryanj]

Postage about £6gbp mate as it will be small.
I can guarantee it should be 5.5 ive fitted  about 6 lengths in the last 3 months.
I dont bother with the clips and never had a leak, the pipes get tighter

[mattsz]

Thanks Bryan!  I think I'm going to stick with what I have for now.  If I need to I can find something local to use as a clamp, even if it isn't the tidy OEM spring clips...

[Bryanj]

I have a big box of assorted sizes of those wire clips give me a diameter and i will see whats in there, 4 of those would be a letter!!!

[mattsz]

If you really want to, Bryan... the ID is 5.5mm, the OD is 10.5mm...

[Bryanj]

I will check what i have and let you know

[Bryanj]

What i have is in the picture and have 10mm and 11mm. How many and which size? Dont go beresk i only have 10 of each!!

[Bryanj]

Sorry put pic in two posts, me and this dumfone are gonna fall out soon!!

[mattsz]

Thank you Bryan but I can get that style on the cheap here - I know a small engine repair guy... 

[Bryanj]

No problem happy to help