HT leaking petrol/fuel cap

[Large Filipino]

Fuel injected Happy Time with fuel pump...MMMmmmmmm....

 

[will_start]

large, you could use my extra big fuel filter, the one that cost me $3. It needs a car fuel pump (duh!) trust me to buy the wrong one .

WS.

 

[BoltsMissing]

Yes, and if thought out properly, mechanical pump and injector via a cam type lobe either at magneto end of the shaft, or the clutch end of the crank shaft.
It's only a vision at this point, but it's possible.

 

[Scottm]

In the time before children, I owned a ski boat. The fuel cap was like yours now Large, but there was a vent on the back of the boat that expelled any excess fuel into the lake but I guess it allowed it to breathe. Boat gas caps shouldn't leak for the reverse reasons we are dealing with (water).
I look at my lawnmowers and the gas caps have holes in the top, with a foam filter then a piece of plastic. That keeps the fuel in and the dirt out but lets the air in. Just like the HappyTimes tank, enough vibraton and fuel will come out of the cap.
Perhaps if I can find some foam filter and make it fit around the breather part of the cap, it will "catch" fuel splashing or evaporating. Won't likely help in the case of a bike tipped over.

 

[Large Filipino]

I'm thinking I should go ahead and get that locking cap,then just drill one or two holes to this regular cap and get that foam Scott just mentioned and gas impervious glue it on the bottom there. That way when riding I can have a cap on and when I park,switch it to the locking anti theft 2 miles no go cap. I'll have to disconnect that chain though. And I thought that's so cool too.
It's nice to have a completly sealed tank to turn your bike upside down for example for wheel changes or what not. And all these little things just add to the individuality of ownership.
I also have another thought. Since I don't need that original cap no more,I'm gonna dissect that puppy and check out how that vent works...maybe..just maybe integrate it into my cap...maybe.

 

[Large Filipino]

HEY! I just noticed googling vintage motorcross bikes that some Yamaha's and Honda's have a tube sticking out of their gas caps. But I don't see the buisness end for it looks like the tube goes in to the handlebar gooseneck?
Does anyone have one of these out there? And can you take pics of that buisness end? I'm thinking if this works for motorcross bikes then this shouldn't be too hard for me to copy.

 

[Large Filipino]

I think I found my answer. They sell the chrome caps separately for 4 bucks at that sporting goods store so I may pick one up just so I can keep my gas sealed while I work on the other cap. Then drill and tap? I'm gonna check out the motorcycle shop tomorrow for this.

http://www.rpamx.co.uk/acatalog/Motocross_Fuel_Caps.html

 

[fetor56]

What about an old tyre valve stem mounted in your tank cap with the top screwed on the stem and very small holes drilled in the top with gas resistant air filter foam inside.You could also have a very small washer the diameter of the stem so the foam can't possibly drop down.

 

[Large Filipino]

That would be cheaper. They want 15 bucks at the motocross shop.
You can just unscrew the valve..I wonder if I could make that a one way valve?
(runs to my scrap tubes pile)

 

[mshagg]

Has anyone considered using a motocross style cap, with a one-way valve fitted into the breather hose, some form of check valve - to allow air in but no fuel out.

A quick look on eBay (australia) shows these check valves for aquarium purposes, to prevent water flowing back to the air pump...