[davijoh]

First timer here, and new rider to boot. Got a 2001 Vulcan 500 running again after sitting for 6-7 years and it runs like a champ, but leaks fuel into the air box when it sits for any amount of time. Looking for some tips to help me troubleshoot.

I had a bad float needle on it that I recently replaced and cleaned the carbs while I had them off though they weren't very dirty. I thought this was the end of my woes, but then discovered more fuel leaking from the air box today when I went to ride it. I know for a fact my petcock leaks (vacuum petcock) but I would think the floats should prevent the carbs from over-filling anyways, right? I have a petcock rebuild kit on the way, but now I'm suspicious that I still have a carb problem. Any suggestions?

Love the bike... just want to get out and ride it more!!

 

[v2stix]

Don't know much about the 500 range as never owned one, but am wondering does the fuel/petcock have three positions on it? Run or on reserve and prime my 800 has this configuration, if yes never leave the lever in the prime position as this will allow fuel to run directly into carbs and eventually into the engine cases and mix with the engine oil, this is made worse if the bike is in a hot climate as pressure can build up in the tank and force the fuel through.
If not then a clean and re-build of the carbs and tap would seem to be the next option.

Stix

 

[davijoh]

Yeah, it sounds like I have the same configuration as your 800 - On, Pri, and Res. I definitely never leave it in the Prime position, but I have verified that it leaks even when it's left in the On position, so I know that's part of the problem. I just thought that having fixed the bad float needle, this wouldn't really matter if the floats shut off the fuel flow properly. Perhaps, as you mentioned, there is some pressure build up that is forcing the fuel through and into my air box still.

 

[davijoh]

Just wanted to follow up and say that after ordering a rebuild kit for the petcock and replacing the seals/diaphragms for the vacuum shutoff, seems to working great now. Rode it into work for the first time today and really enjoyed it. So far, no more gas leaking into the air box and all is well :-D

 

[Cynjut]

If gas was leaking into the airbox, it was probably also leaking into the cylinders, and hence into the oil. Once you get it all checked out, you might consider an oil change.

 

[davijoh]

Good point Cynjut, thanks for bringing that up. I didn't mention it in my posts, but during my troubleshooting, I had to change the oil several times because of this. It looks like there is a drain in the airbox, but the breather tube from the crank case is positioned on the same side as the kick-stand, and consequently, the same side the bike leans when parked so I had some gas in the engine anytime it leaked. A few tricks I learned to detect gas in the engine/cylinders: 1) Check the oil fill gauge - if you have fuel in the engine, the level will go up (mine was solid liquid in the window, tipping the bike didn't lower the level at all like normal), 2) Open the oil fill cap and take a whiff. If there's gas mixed in with your oil, you'll smell it immediately.

Now that I've got it working - I have ridden it almost every day since - I plan on changing the oil again + filter to get out any remnants of fuel in the engine. I'll probably change the spark plugs too for good measure.

 

[Baitis]

Need to replace float needles and check float adjustment. A leaking petcock is only half the problem; the needles should stop flow in to the cylinders.

 

[davijoh]

Need to replace float needles and check float adjustment. A leaking petcock is only half the problem; the needles should stop flow in to the cylinders.

Yeah..I was afraid of that. I already replaced one bad float needle, and checked both float heights (this is how I discovered the bad float needle) - so maybe I should just spend a few more $$ and replace the other float needle as well. Thanks for the recommendation.

 

[Kawasakian]

The neeles will not stop fuel flow into the carbs, because they are set for an idle, which means they must be slightly open, otherwise, you would have to throttle your bike a bit to start. Set the needles using the advice from the "Service Manual". You could always raise them a notch, if you feel the bike is lean, sometimes this will give you much more midrange power.

 

[Kawasakian]

I have a 2003 Vulcan 500 I have gas leaking from air box on the right side also have a line that is hooked up down low between carbs don’t know where it goes any help would be appreciated thanks in advance

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