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Leaking gas from petcock?

7K views 24 replies 8 participants last post by  Spockster 
#1 ·
Just out on a new tank and proceeded to pour some gas in and it started leaking from the petcock. Not sure if the seal underneath it is bad or what. All it has is that circle seal pushed into it right? Or is there a whole nother rubber gasket I'm missing? Also It wouldn't start. Not sure if its cause I didn't have enough gas in it or maybe because I didn't put the cap on it. Gotta find screws for that. Any hell would be great.
 
#2 · (Edited)
Just out on a new tank and proceeded to pour some gas in and it started leaking from the petcock. Not sure if the seal underneath it is bad or what. All it has is that circle seal pushed into it right? Or is there a whole nother rubber gasket I'm missing? Also It wouldn't start. Not sure if its cause I didn't have enough gas in it or maybe because I didn't put the cap on it. Gotta find screws for that. Any hell would be great.
With my old original '86 tank, I rebuilt the leaking Petcock. After rebuild, I still had minor leakage in the area around the Petcock....finally diagnosed it as the tank seal....removed Petcock from tank, cut & added a cereal box gasket between the petcock & tank...no more leakage.
EDIT: Also used gasket sealer with added gasket.
hope this helps
:smiley_th
 
#4 ·
Gonna be home this weekend ?....I'll take a ride down there and help ya out....bout a half hour/40 mins I think....lemme know....I aint doin nuthin, broke, and the ol lady is gone till Tues....what else I got to do ? Lol...bike has almost a full tank....
 
#5 ·
Sorry wolfie. Got a friends bachelor party in Maryland this weekend or else I would definitely take you up on it. Won't get back till mid day Monday. To bad cause I'd like to meet you and KC. Some day soon I guess if I could ever get this pig runnin lol
 
#6 ·
There are also two plastic washers under the heads of the two screw bolting the petrol tap assembly onto the tank. If they are missing fuel will leak. The tap itself is sealed with to the tank with an O-ring, and there are numerous sealing parts in the tap re-build kit. All of these parts need to be in good order for the tap to work and be leak free.
 
#7 ·
Have the washers in there. I may try that cereal box washer lol. Once I have a little money I guess I'll order all the seals for it. Any sites that ya'll use for that stuff? Also may wanna replace the rubber hoses.
 
#10 ·
I searched Ebay for the best deal for a Petcock Rebuild kit, VN750.
......30 some dollars if a remember correctly.

:smiley_th
 
#8 ·
Is it the petcock itself that is leaking, or is it leaking between the petcock and the tank? There is a an 0-ring between the tank and petcock shaped somewhat like a paperclip. If that is the problem, that's all you need. DON'T use any kind of sealer or home made gaskets on it. If it is the petcock itself, it can be any of the rubber parts inside, and there really is no way to tell which. Might be all of them. Replacing all of them gets expensive.

Did you just have the petcock off? If you did, that long weird shaped 0-ring could be completely flattened out. I also know someone who repainted a gas tank with lacquer, put the petcock back on, put gas in the tank, the lacquer melted, and it started leaking.
 
#9 ·
The 0-ring really isn't that big on it. Looks kinda pressed in. I might just order one of the kits on eBay. I thought maybe I was missing a gasket or something in between the tank and petcock
 
#11 ·
take your O ring out and match it up with one from a local hardware store.

Also see if there is any raised paint edges on the new tank you have that might be keeping the petcock from fully seating against the tank.

PM me if you need some help...you are not far from me if you want an extra hand.
 
#12 ·
If its definitely petcock to tank.....almost any True Value hardware has em....the one in Greenwood lake does anyway....bring your petcock, and match it up....no need for fancy, expensive OEM crap....actually, I even have one sitting right in front of me now (I always buy in multiple)....yours if ya want it.......the one in the petcock LOOKS elongated, but thats just because the original retained its shape....a round O-ring that fits the slot nicely will work just fine....
 
#15 ·
Ok got that sealed. With the hoses off, should the petcock flow freely with it open? We got the bike running but it won't stay running. We also found a hose disconnected under the carbs but can't figure out where it goes. Because of that we have some gas flowing out into the ground
 
#16 ·
the stock petcock that has OFF, RUN, RES has 2 fuel lines and a vacuum hose in the center. The vacuum goes to the right carb vacuum port.

Fuel should only flow when the vacuum is applied to the carb nipple in the center....it will not flow fuel if the bike is not running (assuming the petcock is good).


The petcock that has OFF, RUN, PRIMe will do that same except when in the PRIME position...it will flow fuel even if the vacuum is not applied.
 
#17 ·
I have the bottom hose connect from the petcock but there seems to be another hose located more to the right side of the bike. Not sure where it goes. I really need a manual or something haha
 
#18 ·
The vacuum hose on the right side carb, runs back to the suction valve in front of the battery, this suction valve controls the reed valves. The carb port is capped off for the coaster mod and all the hoses deleted.

Then there's a fuel line for the right carb, and the vent from each carb runs to a tee between the carbs, with a single vent line running to an ear, the end sliced at 45° to prevent blockage.
 
#19 ·
yeah...sorry bout that....right carb goes to the emissions crap I removed already.

left carb vacuum port on the stock setup goes to the center of the petcock to control the valve internal to the petcock.


PM me your address and I can stop over to help you...I have a manual and there are photos in the gallery of the carbs and the connections if you need to look at them.
 
#20 ·
Petcock rebuild parts list

I just recently adopted a 1999 VN750, named her Kitty. I have been smelling gas for quite some time now & looked at all the fuel lines but could not find the source; then I stumbled upon this thread. Sure enough, she was leaking from the diaphragm area of the petcock.

From another thread on here I also discovered a wonderful parts site called Partzilla. Some may say they are more expensive but I find their prices to be better than most other sites. Their prices do fluctuate from day to day so when you price it, buy it that same day. Very fast processing & shipping as well.

Anyway, I ordered the parts since their is no rebuild kits available except for the partial kits on FleeBay (which are way more expensive). I plan to rebuild the petcock this coming weekend (12/7/2013). I want to take pix so I can document it for anyone interested.

Here are the list of parts. Total cost including shipping, $33.60.
92081-1240 TAP DIAPHRAGM VALVE SPRING - $1.79
43028-1033 DIAPHRAGM (670B1504 4MM O-RING included) - $12.03
11009-1188 TAP VALVE GASKET - $2.91
92055-1085 (92055A) TAP LEVER O-RING - $2.31
51039-003 TAP FLANGED O-RING (Petcock to tank O-Ring) - $2.91
92022-183 6.2X11X1.5 WASHER-PLAIN (Plastic washers 2 needed) - $1.79 ea.
Parts = $26.65 Shipping = $6.95 (Flat rate based on order total).

Hope this helps anyone interested. Cheers! :beerchug:

----
Here is the link to the diagram for the Petcock.
 
#21 · (Edited)
Anyway, I ordered the parts since their is no rebuild kits available except for the partial kits on FleeBay (which are way more expensive). I plan to rebuild the petcock this coming weekend (12/7/2013). I want to take pix so I can document it for anyone interested.
Wow, a great deal. I paid like $40.00 for my Petcock Rebuild kit off FleaBay.

WTG !
:smiley_th

EDIT: I blew it !
 
#22 ·
#23 ·
Check the facts. Those kits have less than half the list of parts I got for little more than 35% more money. K&L even describe their kit as "not including the plastic spacer for the diaphragm." As for compromised CC, there are no reports of this occurring, I should know, I am an Enterprise Security Analyst by trade. Plus you can use PayPal, one of the most secure methods for Internet transactions. :pepper:
 
#24 · (Edited)
Well there sure was a report here. Sweeping it under the rug might keep it off your radar. I would guess you don't know that one of my debit cards was hacked a couple of weeks ago also.

I think the plastic spacer is reusable in most cases, reports of that here too. $23 vs. $40 is almost a 50% difference. WT said he paid $40 for his, if I recall.
 
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