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Discussion Starter #1
I removed the petcock to carb hose with the petcock in the ON position and noticed a drip. I know this means bad things, so I attempted removal and disassembly, all looked good, but it continued to leak upon reinstall. so, Ill go buy a 91.00 new one. I just dont trust the rebuild kit...do you?
next, I think the gas flows only when the bike is on because of a vacuum tube. but...I did the epa removal thing, so MY tube coming from the petcock is now capped. Is this a major problem? the bike could never have run with only the tiny drip, so im assuming that somehow when the bike is powered on, gas does flow more. im also thinking this issue is why I found gas running out of my tailpipes the other day...and I thnk some gas got in the oil...past the rings, because the oil level is now higher. any thoughts or experience on this/?

thanks!!
nrg
 

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Hi!
As far as I know, there are as minimum two types of fuel taps on VN800 models. (You should consider that when buying repair kits.) Anyway, both types use vacuum. The fuel should not drop without negative pressure form engine side. It flows only when vacuum gets applied. You are right on that. Rebuild kits are ok:) but You should examine the whole condition in general whether and what to buy. I also removed my EPA and in general it has nothing to do with the fuel tap problem.
The gas in oil is a big problem :( I'm sorry about that :(
 

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inside the petcock is a small rubber diaphragm and a spring and a plug, when the air flows thru the carb throat and creates a vacuum this vacuum runs thru that carb to petcock hose and the vacuum pulls on the small rubber diaphragm inside the petcock, and this in turn releases the spring pressure on the plug and this lets some gas to flow thru the hole, the reason you have a drip with your petcock in the ON position is this spring inside the petcock is weak and there is not enough pressure pushing on the plug against the hole, thus letting some gas to drip thru the hole. You have 2 options to fix it, you can take the spring out of the petcock and give it a gentle pull to stretch it a bit -or- you can buy a petcock re-build kit and hope the re-build kit comes with a new spring, either way you do it, that spring inside your petcock is the problem. Watch this youtube video How to Fix Your Motorcycle petcock without a rebuild kit https://www.youtube.com/watch?v=5DqvB_5gP20
 

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Excellent explanation from btom!
But be very careful with stretching the spring! It's calibrated (like springs in carburetor valves) and should hold the exact pressure. If overstretched diaphragm will not work in needed diapason. If it does not work any more, consider to replace.
 

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maybe buying a petcock re-build kit would be better than trying to stretch the spring, so maybe the re-build kits contain a new spring, I don't know
 

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I ordered a kit off ebay and installed it just like the old came out, still leaked, wasted whatever I paid for it. Not saying you might not have better luck, also had gas leak into oil and had to regasket stator cover, ended up ordering an o.e.m. off ebay and now it is fine. Good luck.
 

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Discussion Starter #9
took it off, cleaned it, probably overstretched the spring, put it back. put a cup of gas in the tank...........mopped up a cup of gas off the garage floor and ordered an oem on amazon for 91 us dollars. lol. I got the same luck as old 8hundred on this bike. im not taking any chances this time. Id like to ride this 2k turning into 4k bike I bought someetime before I start collecting pension. next stop, the kawi dealership to see if they can tune my carb to the vance and hines. oh yeah, then I just realized i bought this thing with 17k on it and have NO idea if anyone has ever done the valves. lol. dang.

~nrg
 

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so the whole cup of gas you put in the tank ended up on the garage floor? how did all that gas go thru the petcock like that?
 

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Discussion Starter #11
the rubber diaphragm had deteriorated, and my removal and reinsertion had rendered it useless. as I was pouring in, the gas was pouring out. im enough of an idiot to not have put something to catch it on the ground. oh. and also, the back seat does not clip onto the hooks anymore. Im going to have to redrill the little bar thing under the seat, and move it fwd about 1.8". the seat is all wobbly. Ive been told that happened with this model/year bike. Ill admit the build quality is coming into question.
 

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There is a cheap Chinese petcock that is 100% compatible with the VN800 petcock. The only issue is that the gas line is not the weird hose that Kawasaki is using. For this petcock the gas line is 1/4th of an inch on both sides.
I had the same issue and was able to fix it cheaply with this Chinese petcock. I am saying Chinese because I could not explain the price tag of $10 shipped I got from ebay. Only Chinese can manufacture a petcock, sell it and make a profit at $10.
 

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Ive done that with mopeds and 4 wheelers for the kids, this time I bought oem. I can now say that this is the only functioning part on the bike. still dont run. in fact, before I replaced it, it kinda ran, now that I replaced it, it does not run at all. good times. and btom, the reason a cup of gas hit the floor is that no gas should flow when bike is off. a vacuum hose from somewhere makes it flow properly when on. a good way to tell yours is going to shit is if you turn your bike off, remove the egress hose, and it drips. mine flowed. a cup. on the floor.
 

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I can tell you that the easiest way to solve this problem is to buy a manual shut off valve petcock. I spent somewhere around $20 on a petcock meant for a yamaha raptor 660 that fit perfect. No problems after i switched from the vacuum to the manual. You just have to vacuum cap the place on the carb for the vacuum carb.
 

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Why not just replace it with a manual petcock with a sediment bowl, no more problems. I did this on my 500 800 and KLR.

1 time was enough for me when the gas ended up in the crankcase....I have heard about several others! I was lucky and caught it before I rode out. Never had this happen with a manual petcock.
 

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I can tell you that the easiest way to solve this problem is to buy a manual shut off valve petcock. I spent somewhere around $20 on a petcock meant for a yamaha raptor 660 that fit perfect. No problems after i switched from the vacuum to the manual. You just have to vacuum cap the place on the carb for the vacuum carb.
I did this as well when I found out how much an OEM petcock cost. Works great, just have to remember to shut off the fuel when I kill the bike.
 

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If you get this petcock and remember to use a clamp to secure the gas line to it, you should be a happy customer without having to spend a fortune for a rebuild kit or a new one.
It costs around $9 with free shipping from ebay.
I am NOT in any way or shape related to the seller. This petcock worked beautifully on my 2001 VN800B classic. It should work for any Vulcan 800 of any type and any year.
Link:
Suzuki Lt 80 LT80 Fuel Gas Petcock Valve Switch Pump ATV Quad 1987 2006 | eBay
 

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I went for a ride last night and I noticed my bike was having trouble idling. When I stopped at a light it stalled. I got it started and got back home. I turned the bike off and parked it in the driveway and I saw a steady drip of gas from the overflow line under the bike. I pulled the air filter off and gas was slowly flowing from two small holes in the carb where the air intake is. When I pulled the fuel line off the tap gas was dripping with the bike off and the tap was in the on position. I'm hoping I just need to rebuild the tap. I'd appreciate any advice on this.

Thanks,
Bill
 
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