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Check valve

6965 Views 24 Replies 9 Participants Last post by  hossbuilder
I found this little in line check valve in the Chapperal Motorsports catalog. They call it a Gas Stop 1 way valve that you install in your gas tank vent hose which doesn't let gas spill out of your tank , yet still allows air into your tank so it can vent . I know on my 8.5 gal. tank , I can only put in about 7 to 7.5 gal. before gas starts running out my vent hose so I'm going to give this check valve a try . Just though it was interesting .
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check valve

Hello Jack; Jack Phillips (HAWK88) here. Am interested in how well that works. I'm gathering the materials to go "non-vented cap" on my Boss, ordering quick disconnects for the crossover hose as well. Already (chemically I think) trashing the paint around the filler. I'm very careful with the nozzel, but screwing it up anyhow. I've seen some threads about "filler-protectors" and am seeking council on what works best there too.
Thank you. Ride Safe.
I got a set of gas tank edge protectors from Stamford BH. The ones at this link look exactly like them. The ring screws into the filler opening, and the cap then screws into the ring. So far.....no scratches from a gas pump nozzle.

http://harley-davidson.ridegear.com/cgi ... ?E+scstore

The move must have went well, you're already tinkering again :lol:
Check valve sounds neat, let us know how it works out for ya.

Hawk........if your paint is bubbling around your cap, it is due to the fuel vapors getting under the paint in the neck area and destroying the bonding. Mine has done it twice and the only remedy is to reseal the area where the paint ends at or in the filler neck. Mine has been redone twice with high tech paint sealers, this time I'm going to try mans best friend, clear fingernail polish 8) Good luck and don't let it go too far, it will peel the paint way into the top of the tank if you don't get it under control.

Gas Vent

OK Guys,

Here are some things I learned at the school of hard knocks. Some of it may be useful to you.

Jack - you don't want to block the vent from releasing expanding fuel / fuel vapors. When the gas gets hot and expands (the fuel tank is right above the engine and in the direct sun) it will either; A. Force its way past the gasket on the cap and ruin your paint or B. build up so much pressure it will override the needle and seat and flood the engine.

Tim - go to a hobby shop and buy some "Dope". It is still made and comes in a variety of colors. Paint a narrow ring around the intersection of the paint and the fill hole. It is totally fuel resistant and if you get a color that is close, you hardly see it.

Damn it.......you'd think a guy my age would remember about "dope".....
built a lot of stick&tissue models.......great idea........Saturdays project :)

Neil , I am going to experiment with this valve and if I see or detect the slightest problem with it , out it comes . I know how you have vented your tanks and that is slick , but the vent tube in my tank must be very low in the tank to only allow me to put about 7 gal . before the gas comes out the vent hose and all over the ground especially when it's leaning on the kick stand .. This scares the **** out of me sitting at the gas pump with a big puddle of gas under the bike . This winter I plan on venting my tank like your method .

Neil is so right and you couldn't pay me to try what you are doing by building up the pressure up in the tank. Seldom can you get more than 7.3 or so in the tank anyway so you will just stop a little sooner.

Hawk 88

Same thing happened to me .Kuriakin makes a nice set of paint savers also. I can still see about 1/8 wide inch bubble just barely sticking its head out from under the rubber seal but I am hoping the permananent collar will hold it at bay.
If someone has been in the same boat please let me know if I should take the cap off and seal it . My fear in doing this is the paint cracking if I try and pry it up The paint folds over into the filler area just slightly and I have not figured out how to get between the paint and tank.

HAWK88 (Jack Phillips) here. As usual, THANKS to ALL! If you guys had of been able to brain trust the Desert Shield / Desert Storm thing, I might have been able to be home to see my first GrandChild born T-Day 0f 90!
As well, I should have remembered Dope. ReKitted a few myself, before God invented Digital Radios.
Suppose I should get proper Kurikan Paint savers to fit now, dope all before installation and together (like "ice box" rivets, and use existing vented caps till non-vented conversion time. Thanks again all.
Jack Phillips
Well I guess the check valve idea is not a good one so out it comes . That's the story of my life , Every time I think I know where it's at , someone moves it .
Hawk 88

I forgot to mention the kuriakin paint savers will probably have to have the outside diamiter of the threads ground down a little and tapered on the end to fit . Not a big job.

Bill, HAWK88 here.
E-SPLAIN Please the thread grinding-down thing. Is that like taking a jewelers file to sharp edges, or what. These old eyes have "SEEN THE GLORY" too many times! Or is it something I need to take to a reputable Wrench or machinest? Thanks.
Jack Phillips
Hawk 88

Just measure the outside thread diamiter of your existing caps and then measure your outside diamiter on your new paint savers. If the new ones are to wide and will not thread in just grind them down on a bench grinder by turning the piece as you grind, till they are the right diamiter. If getting your fingers to close to a moving grindstone is not a good thing just get somebody with more skin on their fingers to do it. Took me about 1/2 hour to do by the time I remembered somebody else had the same problem on one of these boards before.


Paint saver thread grinding

Bill, thank you, I'll give it a try. Not too concerned with fingers too close to the wheel, just squeemish about splattering blood on my trifocals!
That, and an extra thick gasket may well solve my problems there. When I have too much fuel in it, and it leaks liquid under acceleration, it comes from under the edge of the cap fairly aburptly. There is so much paint there (whats not chemically peeling), I may have to remove some to get a proper seal there, DOPE liberally for chemical protection, then put the new paint savers in after I get the threads to fit. Does that sound about right? I will also clear the vents well.
Thanks. Ride safe.
HAWK88, Jack Phillips
Hawk 88

There are 2 styles of rubber gaskets that come with the paint savers. once the outer cap is threaded in with the appropriate gasket on ( as per picture in package) there should be enough pressure on the paint and tank to stop any gas vapour from getting under. It remains tight at all times. The actual filler cap screws into the outer cap and is vented . My bike is 2002 and has 1 dummy cap so I got 1 vented and 1 non vented cap. I can still see just the slightest sign of a bubble outside the rubber gasket on mine and am hoping it will be ok without any further repair. My caps have been on a month and were put on about 1 week after first noticing paint lifting. Over that week 1 bubble traveled about 1/4 of an inch outward and other spots were just starting .

Just reread your last input There should not be any gas escaping through your gas cap . Is your present cap vented. Mabye someone with a little more knowlede can jump in . Doesnt your tank have some sort of over fill tube.

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After reading yours, and others posts, I'm about convinced that either my vented cap gasket is ill fitting (worn out possibly), and or the paint build up is too great for a smooth seal. The cap feels firm when it is seated, but I don't feel the "seal / gasket contact" before it gets there. I actually think the threads are bottoming out before the seal has an oppertunity. I'll go ahead and order the paint savers, because of existing damage, and hope the new gaskets seal well between the saver and the tank, and between the cap and the saver. This Hoss has way too nice of a paint job for me to screw it up with negligence.
Sure wish a couple quarts of "Harley Smarts" had of been packaged with this girl when I bought it. Very little of my multi year Jap, German, and previously Brit cycle knowledge is helping much. You and the other Hoss'ers have been my salvation! Thanks.
HAWK88, Jack Phillips


Run, don't walk to the nearest Hobby shop and buy some "Dope". It is a fuel resistant paint. Seal the edge where the paint ends around the gas fill opening.


HAWK, don't use a vented cap! Sooner or later you will have fuel all over your paint. Is your tank vented? If not, I can tell you how to fix it.

Now I am curious . My 2002 350 came with vented cap on the fill side.
How do I vent the tank if I put non vent cap on. Why do tanks have a vented cap along with an overflow pipe. I sound like a 4 year old asking why is it that way questions.

Vented Cap

I agree. I don't know why the late models come with a vented cap.

The "overflow" as you call it is a vent. We have been epoxying the vent in the cap shut. It is not needed and this prevents your paint from being ruined.
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