Fuel is leaking from my carb.

Everything in-between the gas cap and the carbs. Also how the engine inhales.
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pappy1118
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Joined: Thu Sep 19, 2013 8:51 pm
I ride: Black '07 vulcan 500 LTD
Location: Canton, Michigan

Fuel is leaking from my carb.

Postby pappy1118 » Sun Mar 09, 2014 9:55 pm

A few days ago I started to get my bike (07 vulcan 500) ready to ride. I have had the cover off from over the bike a few times to install some goodies during the winter. This was the first time I attempted to start it since Oct. of 2013. It took a bit but started up and I let it run for a few minutes. Still very cold out so I went back in for a while. When I went back to It I noticed a gas smell. I started looking and found some under my carb. There is a slow drip. I'm wondering if this could be from a bad petcock since it happened while the engine was off. I think I turned it earlier but it wasin the on position. I drained most of the gas out of my tank in preparation of removing it to fix what ever. Any suggestions? It had 1200 miles on it when I got it last year and now has just over 5k.
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AKrider
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I ride: '93 Vulcan 500, '06 Honda Rebel, '81 CX 500
Location: Two Rivers, Alaska

Re: Fuel is leaking from my carb.

Postby AKrider » Wed Mar 12, 2014 9:07 am

Our bikes have a diaphragm in the petcock that is supposed to prevent fuel flow unless the engine is cranking (opened by vacuum) so I would go there first. Secondly, any carburetor that is clean and functioning properly should shut the fuel off at the float valve and not leak once the bowl is full to the proper level.

Once you get the tank off to access the petcock, you can easily find a repair kit at Amazon if your dealer can't help you, I would recommend cleaning your carbs as well. There is lots of controversy on the net over this with folks recommending everything from boiling them in lemon juice to "mechanic in a can", since you are experiencing leakage by the float needle and hopefully everything runs fine otherwise I would try the following,,, While the tank is off drain the float bowls with the drain screws at the bottom of each bowl, get a small funnel or fuel bottle and pour Hoppes #9 gun cleaning solvent through the needle valve and out the drains. Hoppes not only cleans your guns very well but it is the solvent specked by Lycoming to clean fuel nozzles on their injected aircraft engines and boy does it work. Next close your drain screws and put some gas in your fuel bottle (or funnel) and carefully start and run the engine for a bit then shut it down and with fuel in the bottle see if the carbs still leak.

If they still leak you can decide if you want to pull them for a full blown cleaning and rebuild or just let the repaired petcock handle the job.

Good Luck
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Triangles
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I ride: '94 Black Cherry Vulcan 500, '06 Candyfire Red Vulcan 500 LTD
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Re: Fuel is leaking from my carb.

Postby Triangles » Mon Mar 17, 2014 9:10 pm

AKrider wrote:While the tank is off drain the float bowls with the drain screws at the bottom of each bowl, get a small funnel or fuel bottle and pour Hoppes #9 gun cleaning solvent through the needle valve and out the drains. Hoppes not only cleans your guns very well but it is the solvent specked by Lycoming to clean fuel nozzles on their injected aircraft engines and boy does it work.


That is an excellent idea! I just rebuilt my '94 petcock and I must have screwed it up. because it leaks quite excessively. I also noticed I had gas dripping out the carb intake too :( It was late so I drained the gas tank and left it for another day. I had suspected my float needle was leaking as I would notice a faint gas odor in the garage after riding. I will add to AKrider's good information above. It is possible that your float has sprung a leak and no longer floats to close the flow of gasoline. So either your float valve is shot and you need to rebuild it, there is crud built up that doesn't allow a proper seal, or your float has sprung a leak. There is another thread on here somewhere that has the part number for the petcock rebuild kits. They are not available from Kawasaki They are an aftermarket part. Good luck.
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Triangles
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I ride: '94 Black Cherry Vulcan 500, '06 Candyfire Red Vulcan 500 LTD
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Re: Fuel is leaking from my carb.

Postby Triangles » Wed Mar 19, 2014 4:32 am

if you can get past the annoying commentary, the petcock in the video is very similar to ours. More so on the EN500A. The reason I share this is to show the part where he stretches the spring. that pushes on the vacuum diaphragm. This was necessary on mine to get it to shut off.

It also gave me the idea to leave the fuel hose off to test for leaks and put a small bit of hose on the vacuum port and suck with my mouth to test the operation of the valve. I had a clear bit of tube going into a gas can from the petcock.

I also had a leak from the diaphragm side Upon further inspection the opening on the petcock side is sort of toilet bowl rim shaped. The plastic piece has a little ridge that corresponds to this shape. For some reason these did not line up rotated 180 degrees. The keys in the plastic would not allow installation in what I deemed to be correct. So I ground off the little plastic nubs (keys) reinserted the diaphragm and installed the plastic piece oriented with the ridge in the plastic piece aligned to the opening in the petcock. Reassemble and no leaks. The only way I see it hadn't leaked before is that the old diaphragm seemed a little thicker than the replacement.

The float valve seals with a rubber cone on the float needle shoved into the incoming fuel port. I cleaned the mating surface on the incoming port with Hoppies #9 and a q-tip and reassembled. This solved my float needle leaking at least for now. The float needle is slightly corroded not to mention 20 years old so I will be replacing them!

Update3-19-14: I ordered two replacements on fleabay for less than $16 delivered. They are all the same from the EN450 (aka 454LTD) to the last vulcan 500 LTD made. They also the same as dozens of other bikes.
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