HT leaking petrol/fuel cap

[will_start]

mine worked too and it was extra snug. in fact mine worked so well,
i can lay my bike over on its side without a leak.
not sure if it would work upside-down, but that would be the ultimate test.
I guess the cap is supposed to seal and they just made it all wrongk.
as can be seen by my pics, I didn't cut the inner diameter, just chose a size that looked like it would work. (I got a refund on ones i didn't use)
it was 2mm thick only. works perfect.
how thick was your plug fetor ?

 

[fetor56]

It was around 4mm but the cap is spring-loaded and adjusts accordingly.

 

[Large Filipino]

I think it's okay as far as venting for it vents by the spring on the tangs that hold the cap down.
I wonder if there's an American part that will do this too.
You Aussies have cool toilets.
Hows the rubber piece in the gas/petrol coming along?

 

[sparky]

mine worked too and it was extra snug. in fact mine worked so well,
i can lay my bike over on its side without a leak.
not sure if it would work upside-down, but that would be the ultimate test.

SWEET!! I'd really like to hear results from the upside-down test, tho.

This thread makes me wonder if these engines really are gravity fed. I read somewhere else that the piston is acting as a fuel pump... but I dunno how true that is. From the sounds of your leakless rubber caps, it might be. Tho, I don't understand why Large had problems with his air tight cap.

???? Confused ????

 

[Large Filipino]

I had problems for I wasn't allowing air in my tank therefore gas couldn't drain out.
The Happy Time cap is different. Even with it sealed like that mod above,because of the spring in the tang,air could get in but not get out. That is why sometimes when you open a cap sealed good like that you get a swoosh. And air can still get in because of the valve in the center,but once it's in it cannot come out.
On mine my cap is simply a screw on like when you screw down a liquid bottle with a cap. The liquid cannot come out,air cannot come in.

 

[will_start]

The Rubber Test, Cap Seal causes Bogging ???

Hows the rubber piece in the gas/petrol coming along?

I took out the cap rubber stored in fuel for the last three weeks
and it looks fine. No detoriation at all. I stretched it and it looked fine.

The only thing I could see, was fine black particles in the fuel mix,
but they could have been there from the cutting process.
So I swished the bottle with water and put it back with more fuel.

Since getting my bike running again after the glue incident, I have noticed that the cap seals "too well".
IE, I will start to get bogging out/stalls after a couple of kms. So I undo the cap and its then all good. So maybe I need to open the holes in the top of the cap more, so it can breath ???

BTW When I lay the bike over for a long time (30 mins) the cap does leak
a small amount of fuel, not half the tank, but more like 50 ml.

For a short period of say 10 seconds, its barely noticeable, say 5ml.

I'll report back in another couple of weeks about the rubber.
See attached pics of rubber stretch test.

 

[fetor56]

Rather wierd...it's taken one month and now it's sealing too well.Too well infact it's creating a vacuum in the tank and stopping the bike because of fuel starvation.I driller a SMALL hole in the cap so we'll see how it goes tomorrow.

 

[Stink Bike]

About a week ago I purchased the 2008 model petrol cap from ZBox (Australia) and so far so good.It doesn't seem to be leaking and I can turn the bike upside down and very little petrol leaks out.

I've only ridden about 5 miles and so far the motor still seems to be getting enough air.

Mick

 

[wheelsy]

i myself have drilled a small hole in the triangl on the top of the cap cause my tank would develop vacuum and engine will stop you could tap the centre of the cap and fit a brass fitting with a tube that runs up hill so the fuel will run back in tank like a dirtbike uno also you can buy aone way valve for aqarium so if power goes off water doesnt syphon out of tank through air pump cars have these valves in the windscreen wash systemyou could put one of these in the cap so air will come in but not out

 

[Stink Bike]

I've been using my new cap for a couple of weeks now and it's been ok but today I filled the tank to the top and it's now starving for air.It seems to run OK on less than half a tank.