Petcock leaking

So after installing everything and starting the bike up I noticed it PISSING gas.

After further investigation skills I noticed the leaking is coming from the Petcock.



The area with the arrow #1 pointing to it is where it's leaking from.

It doesn't leaking when the Petcock is OFF. It drips when it's ON and it pours when the engine is running.

Any advice?

I'd like it fixed for this weekend.

Please and thanks.

 

Hmmm...no tears.



Should I try and adding some sealant or something?

 

At #1 the vacuum pipe is attached. Did you have it removed when you noticed it was leaking? Did you misplaced the pipe, or?
If there are no tears then there must be an issue of installation, but anyway I wouldn't be too eager to use sealant if I wouldn't be sure where the leak is.
Your petcock is different than mine, is it a '86 type?

 

I'm pretty sure that's where it is leaking from.

Not 100% but when it was leaking on the bike that was where I could feel the wetness.

Is this where they usually leak from?

...and yea...it's an 86 type.

 

If the diaphragm is torn then leaking fuel is sucked from the vacuum pipe ending at the cylinder and causing anything from erratic adling to fouled plugs and black smoke.
Another leakage point is at the rotating part of the petcock causing built up of dirt.

I suspect in your case none of them is the cause of the leakage so I would suggest a careful reassembly of the petcock and test to identify where the problem is if any.

 

Thanks for your responses Blitzas.

I ordered the Diaphragm Kit from Honda and I'll replace that tomorrow.

The rotating part of the Petcock doesn't look like it comes apart.


As you can see in this picture ^^^ it doesn't have screws or bolts.

That means the only 2 parts of the Petcock I can disassemble are the Bottom piece and the Diaphragm part.

 

Another question:

When the Petcock is Turned to the ON position, should gas be flowing from the Petcock?

(no, right? Not without the Engine running)

 

The answer is NO, gas shouldn't be flowing unless vacuum is applied to the diaphragm from the pipe which ends at the back left cylinder inlet.
This will happen either when engine is rotating (just with carbs attached, even without ignition will produce vacuum) or with external means.

About the petcock, only serviceable parts is the diaphragm and probably the o-ring of the strainer.
If you drill the rivets, as I did last night trying to bring back to life a totally blocked petcock, you will get more "serviceable parts" but I don't think there are chances to find any spares. Few threads below a fellow did a modification like that.

Unfortunately I will also have to go to some major "innovation" as I cannot locate any '86 petcock for my tank :mmph:

 

If you drill the rivets....how do you re-attach that part?

My Petcock has no screens and no o-ring in that bottom peice. I did put some Gas proof sealer around the threads when I screwed it back in. Looking through the Petcock shows no problems.

I guess I'll have to re-assemble and re attach everything and then fill the tank with gas and see if it drips again with the Fuel Selector set to ON

 

Can anyone else on here tell me where these Petcocks usually leak from?

 

"Can anyone else on here tell me where these Petcocks usually leak from?"


the little hole in the end, usually after a visit with a prostitute that doesn't take care of herself.....hey,you asked.. the diaphram and the O ring are about it unless you take it apart by drilling out the rivets.... sorry to just repeat what was said........

 

I'm just hoping for a magic answer.

This bike is such a fuss :-(

 

There are few points where this petcock can leak and all are already mentioned, so the magic (if any) has gone.
About the o-ring, the original is stated as "gasket", but I am not sure if the shape mine has is formed by the years of being pressed or it was factory formed. I believe a 18.77mm x 1.78mm or a 17.17mm x 1.78mm would do the job as well.
Screens are only good for flakes but not for rust dust. If you have the upper (the one which enters the tank) you don't really need the one of the strainer. I know '86 petcocks might not have screens. If you think you need a strainer screen let me know, I might get you a spare.
After drilling the rivets next is drilling holes and threading M4 (or M3 which will leaves more meat around) , but I don't think I will do all these as I have a '85 petcock that is working. I will probably restore the drilled petcock in a later stage when I will have some time.
You don't have to attach the petcock at the tank to do the test. You can try to verify if it is working by just blowing at the fuel inputs when vacuum is applied (i.e. a syringe with a small piece of tube) and then without vacuum. A spayed solution of dishes detergent and water could also help in case of leaks.

 

You are gaining skillz...if/when you buy another bike you will be an expert...

 

Thanks everyone.

Moment of truth tonight

 

Can you please measure the length of the bronze pipe? from mating surface to the end of the pipe. Thanks.

 

Shit.....it's already sealed in the tank. Just waiting for the sealer to dry.

Sorry.

If it leaks again I'll measure it

 

I don't know what to wish for now ... leak or not leak?

Just kidding, I hope your troubles are over :smile:

 

Hahahaha......thanks blitz

 

Just an update.

Everything that could be removed and re-assembled I put a layer of gas resistant sealer on it.

Everything is ok now and the bike is running great...leak free!