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Thread: Leaky Fuel petcock shut off valve

  1. #1
    Join Date
    Jun 2011
    Location
    British Columbia, Canada
    Posts
    135

    Default Leaky Fuel petcock shut off valve

    I have searched the forum and found handfuls of information, however I am still at a loss and nowhere did I find some pictures to help me understand what I can do to seal my shut-off valve.

    I have attached a couple photos of my problem valve. I soaked it in cleaner and removed all the rust etc and cleaned up the threads.

    Problem I first see is that there is a large clearance between the valve shaft and the bushing inside the valve body itself.

    Next problem is that I can't get a clean turn back and forth to do any lapping of my valve face and seat because when i turn in the spindle it of course seats hard against the valve. (I am use to lapping valves that spin freely).

    I would welcome any suggestions on what might work to get a decent seal. I have read about RTV solutions and cutting o-ring grooves (I like this one). The slop in the spindle has me really worried as obviously I don't really have a reserve. I am certainly open to obtaining a new setup as this one appears to be an aftermarket configuration? or not?

    IMG-20120206-00040.jpgIMG-20120206-00041.jpgIMG-20120206-00042.jpgIMG-20120206-00043.jpgCentral Saanich-20120203-00038.jpg
    Bob Beatty
    AMCA 19209

  2. #2
    Join Date
    Feb 2003
    Location
    High in the B.C. Rockies....
    Posts
    5,308

    Default

    Hey Bob,

    Is it leaking fuel to the carb when shut-off or just plain leaking?

    Have you checked to make sure the top and bottom holes in the tank are in line?

    Is there paint on the underside of the tank where the brass seal sits? If there is, it may leak.

    I think that it's the seal that holds the rod up for reserve. Have you had a good look at it? Does the seal area on the rod show any signs of wear? If it's worn it won't hold the seal up. Is there a chance that the rod is bent? You can straighten it if it is but be super careful. The valve seat can be repaired but it does look like you have a reproduction so I guess it's up to you as to whether you want to repair it or just replace it.

    When one of the "gurus" has a look at your thread, I'm sure a clear solution will appear. If not, I'll hit the books and get you some solid info.
    Cory Othen
    Membership#10953

  3. #3
    Join Date
    Jul 2010
    Location
    Ohio
    Posts
    306

    Default

    My suggestion, take the rod you have a redress the taper either on a lathe or grinder getting the best finish you can. Get a second rod and do the exact same, then machine the threads off the second rod then use this one as a lapping tool(or just take another piece of steel and make a lap simulating the rod configuration-cast iron would be better if available). If it wears while reseating just redress it again and lap some more. Bob

  4. #4
    Join Date
    Jun 2011
    Location
    British Columbia, Canada
    Posts
    135

    Default

    Quote Originally Posted by c.o. View Post
    Hey Bob,

    Is it leaking fuel to the carb when shut-off or just plain leaking?
    Have you checked to make sure the top and bottom holes in the tank are in line?
    Is there paint on the underside of the tank where the brass seal sits? If there is, it may leak.

    I think that it's the seal that holds the rod up for reserve. Have you had a good look at it? Does the seal area on the rod show any signs of wear? If it's worn it won't hold the seal up. Is there a chance that the rod is bent? You can straighten it if it is but be super careful. The valve seat can be repaired but it does look like you have a reproduction so I guess it's up to you as to whether you want to repair it or just replace it.
    Hi Cory, The seal to the tank and around the bango fittings is spot-on, no problem at all, the rod is actually in great shape.

    The issue I have is the seat leaks, not in gallons but it dribbles, perhaps I will have a look today for a piece of similar steel to lap in the seat as BigLakeBob suggests.

    The other thing of course is the large clearance between the shaft and the bushing, there is no way I will have a reserve with that much clearance. I am considering weakening the shaft by cutting in an o-ring groove to seal the bushing and shaft, but I should not have to do that.

    I wonder if there is a place to buy an original or NOS, hmm probably not after all these years and the problems people have.
    Bob Beatty
    AMCA 19209

  5. #5
    Join Date
    Jun 2001
    Location
    Central Illinois, USA
    Posts
    2,129

    Default

    Folks,

    I found it quite disappointing to go through the whole rod and seat dressing routine,
    and even making a PEEK tip for the rod,
    only to finally determine that fuel was leaking around the pressed-in seat.

    ....Cotten
    Last edited by T. Cotten; 02-07-2012 at 08:24 AM.
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  6. #6

    Default

    This has been discussed before. Try this:

    http://www.antiquemotorcycle.org/bbo...aking+petcocks

  7. #7
    Join Date
    Jun 2001
    Location
    USA
    Posts
    200

    Default

    You may also need to align your tank. It is an easy process and v-twin sells the tool.

  8. #8
    Join Date
    Feb 2010
    Posts
    181

    Default

    Quote Originally Posted by silentgreyfello View Post
    This has been discussed before. Try this:

    http://www.antiquemotorcycle.org/bbo...aking+petcocks
    That thread is for an earlier valve.

  9. #9
    Join Date
    Jun 2011
    Location
    British Columbia, Canada
    Posts
    135

    Default

    Quote Originally Posted by T. Cotten View Post
    I found it quite disappointing to go through the whole rod and seat dressing routine,
    and even making a PEEK tip for the rod,
    only to finally determine that fuel was leaking around the pressed-in seat.
    Hi Cotten - I know that you have been on many of these fuel shut-off valve discussion before and I value your learned opinion. I have a newbie question: What does PEEK stand for? (is it the polishing compound).

    Also, does anyone have a suggestion or a source I might approach to rectify or buy refurbished? (I have in the back of my mind the inline valve you suggested to others, and if I can't get this thing to work i will go that route.

    Others have mentioned that perhaps my alignment is off, I think I am good to go for that, I have no issues with the tank seal, only the valve face (and now perhaps its also the valve seat that has a weeping problem), everything fits in smoothly and appears correct, but for now the problem remains, ie the valve face and certainly the issue with the rod and the bushing not being tight.
    Bob Beatty
    AMCA 19209

  10. #10
    Join Date
    Jul 2010
    Location
    Ohio
    Posts
    306

    Default

    Quote Originally Posted by T. Cotten View Post
    Folks,

    I found it quite disappointing to go through the whole rod and seat dressing routine,
    and even making a PEEK tip for the rod,
    only to finally determine that fuel was leaking around the pressed-in seat.

    ....Cotten
    Have you found a way to fix the pressed in seat or do you need a new part? Bob

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