After going for a ride it reeks of fuel around the petcock area, vapor dissapates after a few hours and only has a hint of smell when cold. I pulled the tank today and can't find any leaks or cracked/loose hoses or anything that might cause such a vapor leak. I also tightened the screws holding the petcock on. What could cause this? could this in any way be related to a low rpm lean condition? any ideas appreciated.

 

The plastic things between the air box and carbys on my bike don't fit together very well so I've covered the gaps with tape... maybe you have the same problem?

I'd say light a match and see where the flames go to but that would be irrespoinsible and silly so I won't...

 

Do you have a California model? They had an Air Suction Valve, AVCV, PCV, a Canister, and loads of tubing connecting them. A misplaced hose on these could cause vapor.

 

Don't think for a second that idea hasnt crossed my mind [sm=badidea.gif]

 

For the last few months I too have noticed a fuel smell around the bike. I park it inside my garage, so I notice itthe most after a ride. I never noticed any leaking, but last weekend I was synchronizing my carbs, and afterword I saw a little drip of fule at the bottom of the "Cover Set, Petcock" (Honda description). This is the piece that the vacuum hose attaches to from the #1 port of the intake manifold. I looked closely and it appeared that the fuel was coming out a hole located at the bottom of this part. The Petcock assembly is $100 from Honda. This other item, the "Cover Set, Petcock",(which is included with the petcock assembly or available separately) is about $25. It's on the Fuel Tank microfiche page.I decided it was worth taking a look at to see if it could be fixed, or at least determining if it was the cause of the leak and saving $75. I took it apart and sure enough it was the cause of the leak. It's a really simple device. It's held together, as well as attached to the Petcock assembly with 4 little 4x16 screws. Take out the screws and the assembly comes apart in your hands. ( I made sure the Petcock was in the off position and the tank was low on fuel).There is a spring loaded rubber diaphram inside. The spring pressure holds the diaphram against the Petcock opening and prevents fuel flow. When the engine turns over and generates a vacuum, that vaccum overcomes the spring pressure, and pulls in the rubber diaphram allowing the fuel to flow.

I took the assembly apart, removed the diaphram from the middle part and then cleaned all of the parts. I only used soap a water on the rubber diaphram, as I didn't want to damage it with any solvents. I did use carburetor clener on the other 2 parts though. That worked great. I then put a small film of Vasoline on the surfaces where the diaphram makes contact with the metal parts as well as on the surface of the diaphram. I reassembled the part on the petcock and tested. No leaks or smells. I don't know how long this will last, so I'll order the part anyway. The diaphram had some creases in it's face from where it flex's all the time. I mean it's 13 years old and I guess it can't last forever.


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I've been smelling gas too but it ended up being the tank pressure tube licated at the bottom of the bike . It goes from the tank to the bottom om the bike. If you dont have the tube or the tube is unplugged the smell would seem to come from under the tank near the petcock.
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Update;

Well, I took it for about a 250 mile ride yesterday to the other coast of S. Florida, Marco Island. After returning, I noticed the smell again. I took the seat off, and low and behold that pesky drip at the bottom of the Cover Set. Oh well, short lived fix. No big deal, I've ordered the replacement part, should be here by Friday. It's a 10 minute job to replace, so not a problem.

 

Just to be on the safe side, try taking off the thin suction pipe from the petcock ( i still think that word's a bit sus...), put on a piece of pipe and suck on it. You should heara click as the valve opens. Keep the suction on and check for fuel leaks. I nearly ran into trouble with perished fuel hoses leaking fuel onto my exhaust. They only leak when the engine is running.
Dave.

 

The fuel is no leaking into the vacuum side. If it were, then I'd have a situation where it would be running rich since the vacuum is generated downstream of the carburetors. I've connected a vacuum tool to where the vacuum hose normally connects to and I can here it actuating. There are 2 diaphragm's inside the "Cover Set". You can see the different sizes in the photo's if each side of the part.The small one opens and closes to allow the fuel to flow. The large one is actuated by the engine vacuum. It's the small one that is leaking. There are no leaks coming from around the Fuel hose where is goes to the carburetors.

I received the parts today so I'll be installing soon. I'll post pictures of all the parts.

 

Sorry for the long time between posts. I did get the parts installed. It was easy to do and it worked perfectly. I havent' had any fuel smells after my rides. I've ridden between 900 and 1K miles since doing it and it's great. It sure would be greate if Honda sold only the diaphrams, but I'm not holding my breath. If you have smells or leaks around the petcock area, I would suggest looking into the "Cover Set, Petcock". Attached is what came with it in the kit.



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