HT leaking petrol/fuel cap

This is the greatest day of my life.

YAY! It works!!! No more leaky!
Pic 1 ~ Tank installed,filled it to the start of the threads. Since it's sunk in I may have lost about a few drops of capacity. I mean technically I can fill it to the brim but why?
Pic 2 ~ URURURURUR!!!
Because I'm doing an experiment,Moop. I'm trying to see if your new tank will leak or not.
URURURURUR!!!
Please. Give me 30 minutes then I'll pick you up. Can you give me 30 minutes? Look! I painted your tank and you have a new cover! Do you like it?
URURURUR!!!!!
But chrome is so expensive!
Pic 3 ~ 30 minutes later,Moop is really really ****ed. My Yorkie won't go even near him. But no leak!
Pic 4 ~ But ah. There IS a leak. From the carburator float bowl! No biggie. Shut off the gas valve and you lose what? A few drops?
Pic 5 ~ My fuel line got like all hard. It's amazing how this stuff shrinks after a while. I wanted to replace this and got a new filter so I reached for 1/4 automotive fuel line. This stuff is not the same as the original line. It will leak unless you use actual clamps. The zip ties to the fuel filter seems okay to use,though. The clamp to the carburator was really tight. I needed a screwdriver to push the clamp down to seat right.
You probably noticed I used a different screw for my top hole. That's because I messed up my holeing and I needed a larger diameter screw. I had that laying around.

So now we see that this works,some notes for those that want to copy this bad boy.

1) Remember that this tank is not venting. Especially when it's hot outside just turn the cap about a 1/4 to a 1/2 a turn. That's plenty of venting.Not doing this will pressurize yout tank like when you open your gas cap in your car sometimes and you get that "SWOOSH". I think it's okay to keep it sealed when it's cold outside,but I would turn it anyway when your riding so air can get in as your using up gas. And even with the cap turned a little it's still a way better seal.And you can seal it when it's parked.And you won't lose your cap. It's such an epic win.
2) Wild guess I would say the hole saw you will need is 1 1/2 so bring your empty and cleaned tank with you when you're measuring it out. Trust me. This is the way you want to go.Make sure that the hole saw JUST FITS around the filler tube (with the cap off!). The less metal you take out the better.
3) I got my gas cap and fill tube at the local sporting goods store. Go to the boat section and look for gas deck fill. The one I got is a Chrome Plated Zinc Deck Fill part # 351750-1 made by SeaDog.Soon I'll order that locking cap. It's gonna rule.
4) Drill some holes just below where the threads start so you won't get a huge air pocket in your tank thereby reducing your tank capacity by a whole lot.And you'll reduce the chance of gas splashing up on your eyes cause an air pocket in your tank is trying to get out taking some gas outside with it. It's all theory but I figure drill the holes,save the hassle.
5) When you drilled out your hole,you'll find you need to seat that deck fill to your tank a bit better. Try sliding the deck fill to the tank and applying your hand pressure till the sheetmetal gives and seats the fill deck assembly.Watch that you don't mess up the threads that mount the tank. I used a 2x4 under the tank to clear the threads.Remember if you use this and you slip you can bend those mounting bolts so be careful.A better way would probably be take two 2x4's layed down and drill four holes for your mounting bolts.
With the fill deck seated,line up the screw holes. Take a small drill bit and drill one hole to the top hole using the deck fill as a template,screw it down tight,adjust,then do the same with the other two holes. This ensures it's on straight. Tighten down the screws and check that it's all uniform.
6) Now take it off and sand down the mating surfaces. Rough up the bottom of the deck fill too to ensure a good seal. Then buy that JB weld Waterweld from your local auto parts store. Mead a good sized bead around the bottom of your deck fill. Don't use that rubber gasket (my one and only use for this was when I painted my tank,I mounted this gasket with the screws,therefore the paint didn't hit the mating surface). Put the three screws in the holes and punch the screws thru the thick bead. Now when you put it back the screws should line right up. Tighten it all down a half turn one screw at a time till the clay eases out ensuring you got a good seal. Take off the excess and toss it cause it's already been meaded and will cure rock hard.
7) TAKE YOUR TIME. It should already be ready in less than a hour but give it a day before you add some gas.

MMMMmmmmm...What else should I do? :cool:
 

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That's great Large. Not being able to turn the bike upside down has been a pain for me. To work on the tires, I hang it from the ceiling of my shed.
 
Well Done Man.

You've just given inspirational hope to anyone with a leaking fuel tank,ANY suitable leaking fuel tank......kudos.
WHEN i get mine done with a locking cap i'll let ppl know but i've already learnt alot from your experience.See all these major projects arn't so daunting afterall...just take it one step at a time and you'll get there.
Congratulations again. :cool:
 
I have made a startling discovery. And it's not good. It's not awful but for me anyway,it's not good.
Let me start from the beginning...yesterday.
Tank don't leak yay la dee da take it out for a cruise,cuts off every two miles. So I call it a day uploading pics here then I'm looking at one of my pics and notice that my fuel filter is on backwards! So I clean it out and install it and it's still doing it. Every two miles it cuts off,hold down tickler till gas pours out,loosen the cap so air can get in,again only good for 2 miles.
So this afternoon I'm cleaning out my carb. That little hinge that does that float arm can slide off,BTW,when the float bowl is off,took that hinge off,float arm,that sleeve in the gas inlet then carb cleaner it completly clean,which I didn't see any obstructions but I put it back together these carbs are so simple it's not even funny,and made another test drive. 2 miles later,cuts off.
So I had my cap 1/4 turn loose,then a full turn loose,and on that run I had it half way loose.
So after I tickler the float bowl,I notice bubbles from my filter. Like air is getting in the way of the gas flowing. So while watching these bubbles I take my cap off completly and the bubbles disappeared and the gas in my filter started filling up.
So I ran it again with my cap dangling from it's chain completely off and it ran beautifully for 5 miles till it got dark. No problems.
So here's my conclusion. I will highlight this in red.
The Chineese knew what they were doing by giving us a leaky tank. You NEED LEAKY to make these go!
That's why gas caps have that extra stuff in there.
I'm thinking of an Automotive tank and on some cars you open your cap and it goes "Whoosh!" Tank pressure is okay. When a tank is pressurized,gas can easily come out of the tank. That little special thing in the caps is a one way valve. That one way valve lets air in but not out.
Essentially even with my cap half way off,these Happy Times are 100% gravity fed and I was not letting enough air in my tank. I have to take my cap completly off for everything to work right.
I still like my mod. But you guys with that leaky tank there's still hope.
My boat cap has absolutely no way of venting. So if you want to mod your tank,find an automotive filler neck with an automotive cap.
I can't test this anymore for I modded my tank,but can someone do this experiment for me,especially if you have a virgin tank?
With cap closed and gas valve taken out,blow air in the tank, Is there a lot of resistance? Now suck air out of the tank. If my theory is right,there should be a whole lot less resistance meaning you can suck air out of the tank all day.
I still like my tank. Don't get me wrong. I like the fact that I won't lose any gas to evaporation if I let it sit a while. Then this puppy is yet another anti theft device. #$%@ can only go 2 miles before cutting off. And I don't mind riding with the cap dangling even though I kinda defeated my whole purpose.
Boy if I get that locking cap this is definetly anti theft. @#$% would think he's out of gas.
I hope this helps everyone!
 
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Another thing. I know some guys here use different tanks on their happy times. How are those vented?
 
That's a bit of a shame...i just ordered a cap today,it's a nylon non breathing cap for AU$11 but i havn't physically played with it yet(only pics)
I could have ordered the locking Perco cap for AU$98 but figured it was a ripp-off,and besides AU$98 was way out of proportion for a AU$30 tank.
Maybe by Friday it'll get here and i'll see if it's workable.I'm really not interested in chopping my tank if i think there's no possability that it won't work.........Friday.
Taa for being honest about things Large.
 
I know some trucks you can unscrew the whole thing and is attatched to a rubber hose you can snip off at the local scrap yard. Then just use the filler neck and get a replacement cap for it or use the one on there.
That nylon cap may be good when your parking. Is it supposed to fit over the original hole?
 
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Large:
Naaa it's the complete assembly(looks vaguely like the non locking Perko)
I'll give it the "suck and blow" test Fri(probably).Even if it comes to a pin-prik hole through the screw off cap,or anything to make it breathe(even removing the o-ring)
I'll know more later. :)
 
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I'm doing test as requested, it's HOT outside and ina airconditioned house with HT woes of my own, I'll explain later. ( My HT has No Power, it runs like ****es)
However;
Large Filipino
So here's my conclusion. I will highlight this in red.
The Chineese knew what they were doing by giving us a leaky tank. You NEED LEAKY to make these go!
That's why gas caps have that extra stuff in there.

Yes, because HT relies on gravity feed @ 13.5 avg. psi atmospheric preassure above sea level, I THINK....,!

The Test

The preasure I felt according to your test requirements, seems there is enough restriction to seal the tank, but not too much restriction to inhibit fuel flow as the carby bowl empties and fuel is allowed when needle and seat allow it to, via gravity.
--------------------------------------,
In other words, they have worked out the exact "leak allowance" so to not make it cause to, not-flow, by design of the cap's breathing.

I think also, if the seal is tampered with,it might inhibit this breathing effect to,therefore not allowing air back in as the fuel goes out.

So if we try to add a extra seal cos the cap leaks, it might mess the breathing, but it depends on how the cap is made according to their design, which we have no details as of yet.

My conclusion is, let's say the HT rubber seal is 100% leak proof.
A test will show that the cap will still let air-flow-in as the carby bowl/needle&seat allow it to while the engine consumes fuel, calculated for avg atmospheric pressure above sea level, via gravity.

To solve this issue in once and for all, we need a electric fuel pump and a carby with a needle&seat mechanism that is designed for fuel pump adminisitrations.
If we go to this length, we may as well opt for fuel injected 50cc HT !

OR, a better quality sealing cap that still allows the tank to breath a the correct ~ air-flow allowance.

????


BoltsM
 
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