Topic: Fuel petcock feed tubes

[relative q]

So I took my petcock off today to install it on my new tank, and noticed that the tube(s) that are supposed to be connected to it are missing entirely.  What sort of tubing is used to replace this, and how does it fit into the top end of the petcock?

[number13]

The petcocks had a brass tube which was
pressed, possibly swaged (?) into place.
I would think a good epoxy would do the job also.
I am facing a similar repair on my project
400. The only trick is to be sure you put the
tube in the "ON" hole so that the lower
hole will act properly as the reserve.

[relative q]

What length tube should I buy for my 77 550?  I have to rebuild the petcock anyway, as I discovered today that switching between on and reserve doesn't make any difference; it comes out of both sides anyway... 

[OldSchool_IsCool]

I'm not sure about the '77 550F, but on my K, the petcock is not rebuildable (riveted together)  You might find a replacement petcock in good shape for around what you might spend for a rebuild kit.  You may find that if the petcock wass never intended to be serviced, that a rebuild kit isn't available anyway.

[relative q]

I'll take a look at it tomorrow, but if I recall correctly, mine is screwed together.  Any idea about the length of tubing I should use into the tank?

[TwoTired]

The 77 Cb550 petcocks do NOT have brass tubes on them in the tank.  They have a nylon tube wrapped in a nylon mesh that acts as an in tank fuel filter along with the stand pipe.

Ask your Honda dealer for the in tank fuel strainer, p/n 16952-241-671 (could be 16952-341-671, my fiche is scratched) Honda code 0395582.

Cheers,

[jabbadeznuts]

Don't try soldering... you'll melt the guts of the valve. Dn't ask how I know.

[dustyc]

relative q, if your tank is full enough to work in the on position, it will work in the reserve position as well.  I hope I'm understanding what you wrote and not stating the obvious to you. 

Here's a quick diagram. 

[relative q]

relative q, if your tank is full enough to work in the on position, it will work in the reserve position as well.  I hope I'm understanding what you wrote and not stating the obvious to you. 

Actually, what I was saying is that regardless of the position of the petcock, fuel dumps out both tubes.  I was only trying to hook up one side of the petcock, as I was just attempting my first start, and ended up dumping gasoline everywhere in the process.  Problem was solved by an old fuel hose and a pair of Vise-Grips. 

Needless to say, after today's little electrical incident, I won't be firing her up again until I get her rewired.  Thanks for the help, everyone.

[dusterdude]

gas comes out of both tubes at all times

[relative q]

gas comes out of both tubes at all times

Then how exactly does the petcock work?  From my inspection of it, it seemed that only one feed hole was open at a time, and connected to only one output tube.  I wouldn't be surprised if I were wrong, though.

[OldSchool_IsCool]

I've seen single-tube petcocks and double tube petcocks on these bikes.  That's because there are two ways that stock carb racks were fed.  Some, like my 77 550k, have a single fuel gallary to feed all four carbs.  It has a single fuel line connection point between carb #1 and #2.

Other carb racks have two seperate gallaries with a feed line between #1 and #2, then another between #3 and #4. 

If your carb rack needs only a single feed yet your petcock has two tubes, your petcock (and probably your tank) is not original to the bike.  You can block off the unneeded line or join the two lines together with a "Y" fitting.

[TwoTired]

The CB550F model in 1977 had a single outlet petcock and a "T" fitting to split the fuel feeds for the 1-2 and 3-4 carbs.

I don't have a 76 K model to know if that was a dual or single outlet petcock.  But, prior models were dual outlet.

The dual outlets were fed from a log and both flowed from the selected fuel source.

Cheers,

[WJL75]

My 76K has a dual outlet petcock. 
Fuel is supposed to flow from both tubes regardless if it is on reserve or not.  If you look closely at the diagram above, the reserve is created by the tube that sticks up and into the tank.  After fuel drops below that opening, then fuel can only pass through the petcock when you swich to reserve, whick opens the lower holes at the base of the petcock.