Author Topic: 78 CB 550K PD 46A Fuel Rail Tube O-rings  (Read 711 times)

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Offline joegeis

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78 CB 550K PD 46A Fuel Rail Tube O-rings
« on: June 03, 2023, 07:12:59 PM »
I'm working on rebuilding my carbs, but noticed that the o rings on these tubes are hard as rocks and turn fairly easily with my fingers. These o rings have been dry for about 20 years. Should I change them? I've been reading that people are actually having more problems with new o-rings, potentially due to the introduction of ethanol. I purchased this kit, but the site doesn't specifically call out all the o-rings that are included. I kind of doubt it, since I would need 6 of them. Is there a place online I can find them? I'm not sure exactly what they are called.

It is listed as component 1 in this diagram, and the link leads to a rebuild kit that looks similar to what I have already purchased.

Offline Deltarider

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Re: 78 CB 550K PD 46A Fuel Rail Tube O-rings
« Reply #1 on: June 04, 2023, 12:50:25 AM »
First step is to bring them in a natural state which is wet. Once exposed to gas again, you may see some initial leaking. Hopefully they swell back to their original size. The ones on my 1976 built CB500K2 are 47 years old and still seal perfectly.
I have warned countless times. Too many here separate their carbs for... nothing.
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Offline joegeis

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Re: 78 CB 550K PD 46A Fuel Rail Tube O-rings
« Reply #2 on: June 04, 2023, 06:00:09 AM »
You or someone else warned me in my build thread,  so I didn't pull them apart.  That said the tube between carb 2 and 3 did come out accidentally.

Offline joegeis

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Re: 78 CB 550K PD 46A Fuel Rail Tube O-rings
« Reply #3 on: June 05, 2023, 10:43:05 AM »
To clarify my question - Where can I get these o-rings, highlighted yellow and circled?

Offline grcamna2

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Re: 78 CB 550K PD 46A Fuel Rail Tube O-rings
« Reply #4 on: June 05, 2023, 10:54:14 AM »
I just looked at an online Honda parts supplier and those rubber o-rings are available from Honda.
I highly recommend using only Honda OEM rubber parts inside your carbs:the fuel w/ Ethanol in it now will eat-up any other type of rubber o-rings plus these parts are still available in a complete kit through the online parts suppliers.
A complete kit from Honda has all the rubber seals & o-rings needed;they're all numbered '1' on the parts page.
75' CB400F/'bunch o' parts' & 81' CB125S modded to a 'CB200S'
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