Topic: Petcock Question (PICS added)

[DaytonGuy]

Well I finally started tearing down my 77 550K the other night.  I have pics and will start posting as soon as the rebuild is moving at a faster pace.  I have one question that has been bugging me.  I took the petcock off of the tank and noticed that the white plastic tube appears to be stuck in the tank.  Is that piece supposed to be attached to the petcock?  Did it break when I took it off?  I didn't try to get it out, but it it was flush to the male connector where the fuel cock was attached?

The whitish thing with two holes inside is really soft.  I tried to use a pair of needle nose pliers to pul it out but it was obvious that I would mash it all to hell if I kept going...


And here's the petcock....



The only thing that came out with the petcock was a badly deformed rubber o-ring seal.

Thoughts would be most appreciated.

Thanks

Chris

[Diebold]

I did the same thing on my bike, too.  It does belong on the petcock for the regular "on" position and the little tube that is still on the petcock is for the "reserve" position.  It will work without the long tube but be careful not to run out of gas as you won't have a "reserve" position anymore.

[mgmuellner]

I hate petcocks & those damn tubes.  Almost always end up with it stuck in the tank.  Anybody run a more modern vacuum petcock?

[DaytonGuy]

So there are supposd to be two tubes?!?!  Well then I guess they are both still up in the tank.  Can they be reattached to the petcock or did they break off?  It doesn't look like your can stick them back on there?

[azuredesign]

There are two different petcocks used that I know of, the type prior to '74 or '75 has a rounded removable bowl with built in filter. The later model is simpler, without the cleanout bowl, and is on the other side of the tank. I believe the later model only has 1 tube, I can't remember if the earlier type uses two tubes.

[walkingchaos]

yes the earlier bikes have 2 tubes.

[DaytonGuy]

When you say on the "other side of the tank"...which side are you referring to.  Mine is on the left side as you are sitting on the bike.

[TwoTired]

Looks like someone assembled your tank with the wrong parts.  Or, they adapted an earlier F tank to your bike.
What is the diameter of the petcock bung?

http://www.cmsnl.com/honda-cb550k3-four-usa_model1015/partslist/F++12.html

Cheers,

[DaytonGuy]

TwoTired,

Good to here from you as you seem to be the recognized expert on the 550's.  I sent you a PM regarding a question about my carbs at the suggestion of SteveD CB550F.  I think I figured it out.....but if you have a spare moment some validation from a Pro would be nice.

About the tank.........

It looks like it's about 15mm inside diameter.

Now that you mention the F model possibility....I remember when I originally got it I think it had SS emblems on the side covers although one emblem was broken.  I had always thought it was an SS until I found this site and starter learning a little about it.  The frame tag and the title definitely say 550K.  I don't know much about this bike, so it very well could be an F model tank.

Any idea which one, or how I go about getting the parts for the petcock?  And what about the white thing in the tank, can I pull that out with the pliers or can I clean/rebuilt the petcock and reinstall it on the tank as-is?

Thanks again for the reply.

[TwoTired]

The older tanks have a 3/4 tank bung and the K3 tanks have a 5/8 tank bung.  This is a thread peak to peak diameter measurement.

If yours has the smaller bung, it's no wonder you're having a #$%* of a time getting that filter/stand pipe out of the tank as it was supposed to go into a larger opening.  That style had a "sock" over the stand pipe inside.  I wonder if it is still intact?

The two square holes you see are the main and reserve feeds to the petcock.  This style uses a thin rubber gasket to keep the two feeds separate to the petcock.  The in tank filter is keyed to the petcock with a flat on one side. A simple oring may keep it from leaking.  But, it won't provide a separation and thus no effective reserve setting.

The K3 petcock has a round columnar filter pressed into the bung and an oring for the seal.   The petcock has the actual stand pipe and the reserve feed at the union.

Any chance you can punch the Previous owner/mutilator in the nose?   

The 77/78 model petcocks with the small tank bung are hard to find matching petcocks that fit, discontinued by Honda.  There is a thread in the tip & tricks about rebuilding these as they are riveted together.  If you don't mind a different outlet position, I'm pretty sure a CX500 petcock will fit on the small tank bung.  And last I checked, were still available from Honda.  Otherwise, a used one is your only avenue to amend the apparent kludge you have.

Cheers,

[DaytonGuy]

Punching the PO in the nose would be a good idea...if I could find him.  Hell, I'd just like to ask him what these parts are from.

I checked the bung size and it's 3/4 so it looks like the tank is an older model tank than the 1977 bike I have, or at lease I think I have a 77.  The way this is going, I'm starting to wonder.

I guess I'm just going to yank that thing out with the pliers.  It will get f@#$ed up, but it probably needs to be replaced anyway. At least that's what I'll keep telling myself as it gets mangled.

My petcock does not have a stand pipe and a reserve feed attached to it, and there is no sign that they were broken off.  I did notice the flat spot that keys it to the stand pipe. Also, it is not riveted, so it will be easier to rebuild. 

What make and model would you think I should search for when looking for a rebuild kit?  I may only need the standpipe and gasket.  I'll know that when I get in there and look around.  That's next on the list after the carbs.

[TwoTired]

The earlier F model tanks had two outlet petcocks to feed the two inlets on the carbs.    Your carbs have only one inlet.  So you'll need a T fitting or plug one outlet.
K bikes from 75 and 76 used the same petcock (two outlet).

I don't know what your petcock came from.  Might be able to make it work with the part in the tank if it isn't too mangled.

Cheers,

[DaytonGuy]

Thanks man!

I think my petcock is in pretty good shape, so I'll look for a standpipe and gasket and run with it.  Otherwise, I'll just sit down and cry for a while.......lol

[DaytonGuy]

John,

That about sums up how I feel.  I'm trying to do this on a budget so any part I can clean and reuse is almost a necessity.  Having to replace a part simply because it's stuck and I can't get it out without killin it really sucks.  I hope I find that it's clogged to hell and unusable when I pull it out.  That'll make me feel a lot better.  Plus...$28 buck for a little plastic tube...DANG!!!!

On the other hand, it could be worse.

[troppo]

try bending the last 1/8th inch of a bit of wire to 90 degrees, carefully feed that into one of the holes and then twist it, that should give you a "hook" to pull it out with

[DaytonGuy]

Well, well, look what I have...



Troppo.  The wire bent as a hook was a good suggestion, but I didn't have any wire stiff enough.

I resigned myself to the fact that I would have to replace it and just pulled with a steady firm grip using the pliers in the pic.  It slowly slid right out, and it looks to be in GREAT shape.  The screen sleeve is still intact.

I think the PO inserted the standpipe into the tank, put the rubber o-ring in the petcock and tightened it down.  The o-ring would not let the end of the standpipe slip past and seat into the petcock properly and as a result, it pressed it all the way into the tank bung. 

I assume proper installation is to insert the standpipe into the petcock so the flat spot allow for proper seating AND THEN put the o-ring around the standpipe and into the petcock.  The o-ring will not let the standpipe past and will keep it pressed firmly against the petcock allowing the holes to line up, thereby allowing proper operation of the reserve fuel feature.....

[TwoTired]

I assume proper installation is to insert the standpipe into the petcock so the flat spot allow for proper seating AND THEN put the o-ring around the standpipe and into the petcock.  The o-ring will not let the standpipe past and will keep it pressed firmly against the petcock allowing the holes to line up, thereby allowing proper operation of the reserve fuel feature.....

There is a D shaped thin rubber gasket with two holes in it the same shape as the mating portion of the fuel screen that seals the two fuel feeds and keeps them separate.

The other proper seal is a square section seal that mates the bung rim to the petcock land.

Cheers,

[DaytonGuy]

Ya see, this is why I love these forums!

Thanks TwoTired, I'm sure I will need to tap into your infinite wisdom many more times before I'm done.