Petcock fix with pics
 

Unknown #1 is the vacuum hose that makes the petcock work, and the one that people often mistakenly put on the air vent. (that creates PVLIR)

Unknown #2 is the tank vent (allows air into the tank to prevent it collapsing as the gas comes out)

Unknown #3 is the overflow hose (connects to the recessed part around the fill cap to drain excess gas from overfilling the tank)

good write up, thanks.

i have a rip in my petcock diaphragm also, parts should be here today :) did this fix your running issues? Im running really rich with poor low to mid performance.

Bit of an old thread revival. My petcock is leaking and I want to rebuild it, my Honda dealer cannot find a rebuild kit although he can find the part number on the bag below:

His computer says "cover" when he punches in the above part number, but it is about $45. Has anyone else had any luck ordering the above part number? Does it include all three pieces that the above photo shows? I PM'd the OP for input but without a response yet I am getting impatient (sorry).

The parts guy wants me to buy a whole petcock saying Honda does not show a "rebuild kit"...Frankly, that makes me want to chuck the whole bike in the crusher and move on.

Having had to replace two already, I have a complete rebuild kit on stand-by in case it happens again (won`t have to worry about any backorder silliness raining on my parade)...

Thanks for sharing. I think it's time to do the rebuild on mine because it doesn't shut off completely.

I was advised by a dealer that I had to buy the entire assembly for around $200. :eek:

I think, if I am remembering right, if your spring is fine, there are several years of goldwings with similar petcocks and the diaphragm from their rebuild kit could be used.

Thats what they tell me, don't do it...I purchased an after market rebuild kit today (contains all the rubber pieces, screws and spring) on ebay from these guys:

http://stores.shop.ebay.ca/Sirius-Co...__W0QQ_armrsZ1

Only $21

I found this rebuild kit on ebay too:

http://cgi.ebay.com/ebaymotors/HONDA...item58882b3779

JB

And it hasn't worked, I have carefully re-assembled this petcock three times with the above rebuild kit. Sometimes it works until I apply a vacuum (suck on the hose), at which point gas flows and removing the vacuum does not stop the flow.

Other times I assemble it and it leaks almost immediately.

Frustration is setting in as this bike seems to be fighting me every step of the way, it does not want to run again.

I am beginning to think it was not assembled properly by a PO (certainly the vacuum port points straight down, not to the side as it should). Does anyone have a drawing or an explanation of how to assemble it properly?

I have assembled it in a way that seems self explanatory, and in the same way that I originally disassembled it.

Any information would be appreciated, thanks.

The port pointing straight down on the petcock is the went for the backside of the membrane... That should not have a line on it... The line on the middle of the backside should most definetly go to the side... Look at the pics in the top posts...

Quick question while there are pics, but do all Hawks have the petcock mounted to the bottom of the tank?

I only ask because my 2001 has it attached to the frame next to the tank mount.

Makes it a bit more interesting when removing the tank.

BBB

Nope... 97-00 has them on the tank, the newer all have them on the frame like yours... Why remove it? Just stick in the hinge and tilt them back with a rag in between... If necessary it's one bolt to remove that from the frame...

BTW that's mainly used to lift at the rear end of bikes for various purposes, I was just using it so I wouldn't knock the tank over... Just don't do that with a full tank or pinch the overflow and vent lines first...

Agreed, the vent is not covered.

On my last attempt at petcock re-assembly I did rotate the port to the side again. This did not help, it leaked everywhere long before any vacuum was applied.

Not sure why the port would need to be sideways, when I look at the cover I cannot see a difference, I assume Honda must have been worried about the vacuum line getting kinked and not releasing (or building) a vacuum.

I think I have found the cause of the problem, but I have no idea how to fix it:

My vacuum is not releasing, when I held the diaphragm "sandwich" together and used a tube to suck (with my mouth) on the vacuum port it would easily draw the diaphragm in, but when I stop sucking the vacuum does not relieve. In fact I could let go of the "sandwich" and the vacuum is strong enough to hold it together, regardless of the spring attempting to force them apart.

This is consistent with my findings of the petcock typically working immediately after assembly until I apply vacuum once at which point the petcock never closes again.

The reason for this could be one of two things:

• I can only blow/suck through the vacuum port in one direction (suck). I cannot blow through it at all. In effect this is functioning as a one way valve. Is this the way it is supposed to be? If so, how is the vacuum relieved to close the petcock?
  • I attempted to force some WD-40 through the port (using the WD-40 straw), I could not get anything to flow through it.
  • It does appear that there is some basic mechanism (another diaphragm?) on the vacuum port, I could see no easy way to disassemble this to inspect it.
• This is the way it is supposed to function and I have not waited long enough? Does this vacuum port allow a VERY small amount of flow back through it, requiring a few seconds or a minute to close it?
  • This seems unlikely to me because of one past experience: Last fall when I went to drain the floats it seemed like an awful lot of gas was being drained (certainly more than the float bowl/hose could hold). I didn't think anything of it at the time as my reason for draining the carb was to get Stabil into the float bowls more so than drain the floats. Of course my new found knowledge of this petcock has shown me that this would not be possible.

I am looking for any thoughts on the cause/solution.

Thanks.

Bump

Hope I have not stumped the gurus....please help.

Am I looking at a new petcock?

I ordered Honda part #16953-ML0-034 from the dealer. Should have it in a day or 2 so that I can re-build mine.

I would just make sure I pay attention when I take mine apart, and then re-assemble it properly.

Sounds simple enough, not sure why you are having problems?? :confused:

Attachment 27243

I am not sure why I am having problems either. When you take yours apart, can you please let me know if you can blow/suck air in both directions through the vacuum port?

Mine is uni-directional so far, not sure if this is correct or not. If this is correct I have no idea how the vacuum is supposed to "release" to stop flow.

Thanks.

I remember hearing that you can empty the tank by just providing suction on the petcock for a brief moment.. So that sounds normal. Perhaps there is positive pressure in there for a second when you shut down? Or perhaps it shuts off if there is no fuel flow?

AFAIK it's a combination of no pressure, the spring and no flow... Ie as long as you have fuel flowing, it will stay open without pressure... That's normal... So for all I know, your petcock should work as intended kraher... Dunno what tests on the bike yielded? Or have you only tested it off the bike?

BTW What is it with you guys and WD40? It has absolutely no business near a fuel line, let alone the petcock... It's not a wonderful multi use chemical that cures all ill's... It'a giant PITA that messes up most things people try to use it on without knowing the effects... Take that petcock apart and clean every last molecule of WD40 of those membranes or you will be replacing them in a few months time...

Kraker - mine does not immediately turn off either - takes about 5-10 seconds to finally stop flowing. I can't imagine that it would be critical though.

Thanks for all the replies, I was beginning to think I had stumped the gurus. :eek:

The way I originally discovered the "problem" was that I disconnected the fuel line after the bike had not run in (at least) a few days and gas started pouring everywhere. Luckily I was able to plug it with my finger and had an 8mm wrench within reach to close the valve.

I guess I can see the vacuum taking a few seconds to stop flow, but days?? If it is days why not just have a gravity feed? I could easily live with it this way if I could turn the gas off without lifting the tank. I am not a fan of gas-oil or hydro-locked cylinders.

Unless, as said by lazn it takes a low flow condition to close. But, the testing I did most recently did not even have the petcock assembled, just the back "sandwich" (no flow whatsoever) and it still was not releasing the vacuum. If I have nuts to temporarily assemble the sandwich I can perform a longer than 10 second test.

Regarding tests on the bike: What tests can be done? The bike runs fine and is clearly getting fuel. Disconnecting the fuel line(s) after not running or cranking in days results in fuel gushing everywhere. I think the float needles are holding off the flow as they should, but I don't like relying on that too much.

WD-40 is about as easy to buy in North America as milk, I think that is why it is so widely used. What would you recommend for cleaning fuel lines and other rubbers?

WD-40 was merely used because it has that convienient "straw" that I thought could be used to clear the vacuum port...to no avail. In my experience WD seems safe for rubber, but I am no expert and am certainly not going to pass that on as truth.

Thanks again for all the help...god I love forums for troubleshooting. :kneel:

I found 4 correctly sized nuts, it has now been about an hour since the vacuum has been applied and the diaphram/spring has yet to "return".

I'm stumped, what exactly is the point of the vacuum petcock if it never closes?

+1...WD40 is petroleum distillate, which will eat up rubber or neoprene eventually. To slip on fuel lines more easily, I use carb spray. It also has a handy little red straw.

It should be fairly obvious... Clean stuff with fuel...;) That's after all what the fuel line is made for...;)

BTW, that's not right... It should take a while and all, but it should close...

Whew,
I'm glad I don't have this problem...however, my 01 has the petcock mounted to the underside of the tank. Is this specific to the 19L Euro tanks?

Gasoline is a distillate of petroleum as well. WD40 is mostly kerosene. It's also safe for most rubber. Again, depends on the type of rubber you're talking about. They make "rubber" o-rings out of hundreds of different compounds.

The diaphragm of a petcock is not the kind of rubber that likes WD40... But yeah, I know it comes from basically the same base product...

I have been at work for a few hours, but before I left the petcock had still not released. I left it overnight.

The thing is, unless my vacuum port is buggered and only flowing one direction this makes perfect sense to me. There is no way for air to get back in and allow the spring to push the diaphragm back.

99 VTR1000 for sale...cheap, problems unknown with petcock.