Topic: 550 Petcock help

[ricvicious]

I am looking to replace a leaky petcock on my 1975 (manufactured in 11/74) CB550K.  The serial number is 1224111 which lines up with a model year 1975.  However, I have ordered two different petcocks that are supposed to fit that year and neither has fit my tank.  The bung on my tank measures 16mm and it is a dual output petcock.  Is it possible that the PO, besides butchering the paint job, switched the tank on the bike to another model year?  Does anyone know where I can get a replacement petcock or a rebuild kit?

[Tews19]

Why are you replacing the petcock? Why not replace the o ring where the 2 screws and cover plate cover the o ring?

[ricvicious]

The little plastic cone in the petcock is broken.  Thats why i was asking about a rebuild kit.  Do you know if they make them?  Does it even matter that the cone is cracked?

[Tews19]

http://www.ebay.com/itm/Genuine-Honda-Petcock-Strainer-Set-16952-341-671-CB400F-CB500T-CB550-CB750-/191586012415?hash=item2c9b6a8cff&vxp=mtr


This?

[Tews19]

or this???

http://www.ebay.com/itm/1975-HONDA-CB550F-PETCOCK-/281705625451?hash=item4196f6b76b&vxp=mtr

[ricvicious]

Thanks Tews! Do you have any idea what year this petcock was used?   

[jamesbekman]

Its a one year off petcock and its rare and the replacement is like $100.

From what I remember its on a 75/76 CB550 and a later model CB750...  Id just replace the rubber on the petcock and that should treat you right.  Dont over tighten it and break it like I did. 

You can get a single fuel output petcock for it from a certain year CB750 as well.

Cheers,

James

[jonda500]

I have a 75 cb550f which I bought a 78 550k tank for- it has the same little 16mm outlet and I found an old dual pipe petcock that fits it on an unknown model tank I have. After many ebay fuel tap searches I came to the conclusion that I have fuel tap #16950-292-000, and that it fits these models (and probably yours too)

1966 Honda CB450
1967 Honda CL450
1968 Honda CB350
1968 Honda CB450K1
1968 Honda CL350
1969 Honda CB450K2
1969 Honda CL450K2
1970 Honda CB350K2
1970 Honda CB450K3
1970 Honda CL175K4
1970 Honda CL350K2
1970 Honda CL450K3
1970 Honda SL350
1971 Honda CB350K3
1971 Honda CB450K4
1971 Honda CL175K5
1971 Honda CL350K3
1971 Honda CL450K4
1971 Honda SL350K1
1972 Honda CB350K4
1972 Honda CB450K5
1972 Honda CL350K4
1972 Honda CL450K5
1972 Honda SL350K2
1973 Honda CB350G
1973 Honda CB450K6
1973 Honda CL350K5
1974 Honda CB360
1974 Honda CB360G
1974 Honda CB450K7
1974 Honda CL360
1974 Honda CL450K6
1975 Honda CB360T
1975 Honda CL360K1
1976 Honda CB360T
1978 Honda CB550K 
1978 Honda CB750A 
1978 Honda CB750K

Hope this helps, John
EDIT- err you wrote 16mm but the pic you posted has 19mm diameter outlet- looks like you need the rare $99 one - sorry!

[Scott S]

 If the plastic cone inside the petcock is broken, you're screwed. Drop a Benjamin on the correct replacement.
 If its the filter inside the tank, you can use that kit posted earlier.

[ricvicious]

John- You are correct!  I didn't realize that the 0 was offset on my caliper.  So it's a 19mm bung on the tank.  I'll look around for some parts or a replacement.  I'll certainly try to replace the O-Ring first to see how I do. 

Scott- I'm not sure if the washer/lip on the cone is cracked off or thats the way it came.  I'll attach pics for review.  I have never taken one of these petcocks apart.   

Thanks for the input!!

[turboed13b]

The petock is fine just replace the oring. I have 5 of those petcocks  and they all let a little fuel past when off so don't worry about that it was a poor design.

[Scott S]

 You MUST have a good in tank filter with that petcock. Any bit of trash that gets in there scores that cone and that's what makes them leak. Honda realized this and changed the design after one year.

 In fact, here's the note that comes with the new petcock.

[ricvicious]

So I would imagine that my (semi) rusty tank paired with this petcock is not a good combination! Do you happen to have a part number for that petcock?
 
Have you ever seen a 19mm to 16mm reducing nut? I wonder if that is an option.

Thanks again! 

[ricvicious]

Do you think something like this would work?

[Tews19]

buy 5 gallons of Vinegar. Soak in the tank for a few days.  Then pressure wash the inside. Use baking soda and fill up the tank full. Shake the tank to coat the tank with the baking soda. Than flush tank again several times. Fill with gas after as the tank will lose most if not all rust inside.

[jonda500]

So I would imagine that my (semi) rusty tank paired with this petcock is not a good combination! Do you happen to have a part number for that petcock?
 
Have you ever seen a 19mm to 16mm reducing nut? I wonder if that is an option.

Thanks again!

that petcock is part number 16950-374-671

the already longer petcock may be too low with that adapter added?

[Scott S]

 The petcock you have pictured isn't the same. Here's the one he needs:

[jonda500]

The picture I posted is of the common cheaper petcock he's thinking of using with an adapter - I don't see any mention in the adapter description of the thread pitch - you'd want to make sure it's the right thread ricvicious