Gas cap leak

[herbie]

First fill up on my new Brozz resulted in a wet tank from the gas cap leaking, next fill up I didn't put as much in and it was better. But I like to take long rides sometimes and I like plenty of gas so thought I would try something to see if it would help. I took an O ring out from my trusty ole harbor freight kit and found one that would fit over the locking mechanism and under the rubber seal like in the picture. I only filled it up once so far but it didn't leak at all, I don't know the long term effect of the O ring but I will see how long it lasts.

[NzBrakelathes]

As long as the cap can vent so it doesn’t create a vacuum and stop fuel flow

[goat67]

Originally Posted by herbie

First fill up on my new Brozz resulted in a wet tank from the gas cap leaking, next fill up I didn't put as much in and it was better. But I like to take long rides sometimes and I like plenty of gas so thought I would try something to see if it would help. I took an O ring out from my trusty ole harbor freight kit and found one that would fit over the locking mechanism and under the rubber seal like in the picture. I only filled it up once so far but it didn't leak at all, I don't know the long term effect of the O ring but I will see how long it lasts.

Take a dremel with a cut off wheel to that cap.
In you picture the part that extends down can be cut off to just below the lock tabs.
I had the same problem until I did this.

[chazglenn3]

Same issue with the Brozz I bought. I'll take my Dremel to it eventually.

[PeaceSportsAtlanta]

Originally Posted by herbie

First fill up on my new Brozz resulted in a wet tank from the gas cap leaking, next fill up I didn't put as much in and it was better. But I like to take long rides sometimes and I like plenty of gas so thought I would try something to see if it would help. I took an O ring out from my trusty ole harbor freight kit and found one that would fit over the locking mechanism and under the rubber seal like in the picture. I only filled it up once so far but it didn't leak at all, I don't know the long term effect of the O ring but I will see how long it lasts.

From Bashan
"We designed a vent hole on the fuel tank cap. The fuel can not flow to the engine smoothly if we block this hole. The gas can not flow out if the fuel tank is Vacuum. It is not a problem, most chinese bikes are the same design."


Basically if fuel level is over the bottom of the cap, the vacuum can build up. I need to try @goat76's repair. In theory, I see no reason why it would not work as its just raising the vent hole higher in the tank.

[herbie]

I just wanted to update this just in case someone else has this trouble. The O ring absolutely did not fix the leaking cap, as you guys who have dealt with this probably already knew.
I took a long ride yesterday and filled it up a little more than I have been and it leaked out for a bit. Nothing worse than just starting a long ride smelling like gas, but the wind took the smell away in short order. Anyway today I decided to take the cap apart to more than anything see how the vent works. When I popped the end cap off I found a problem right away, I'll see if this cures it if not I will drill a small drain hole in the side to allow fuel to drain back to the tank like Jerryhawk suggested in another thread. If that doesn't work I'll try goat67 trick and cut the end off and if that doesn't work I am going shopping for a Japanese cap to replace it.

[herbie]

The check ball is out of the tube that blocks flow.

[herbie]

I believe this is the correct place for the check ball.

[herbie]

Originally Posted by jeffrey

Just cut the bottom off and be done with it. I took mine apart but couldn't get it back together so I cut the bottom off. Yes the ball goes in the tube like your picture shows. If you pull out the second plastic piece you will see a little hole in line with the cap locator then there is another hole out by the edge of cap that is the vent. If you don't cut it down it will more than likely still leak because the cap dips into the gas with a full tank. It is to long.

Thanks for the input Jeffrey, I did take the second plastic piece out and blew through it to see where it vents and I did see the hole, I may end up cutting it but I really want the cap to work as designed. I think with the check ball it should stop unwanted gas from spewing out if the tank isn't overfilled. I will try fueling a few times and see what happens. I've seen may caps like this before and they didn't leak so we will see. Anyway thoughts always appreciated!

[goat67]

Just cut the thing off and be done with it I can fill my tank nearly to the top now with no worries. No down side to cutting it off.

[herbie]

Well I decided not to alter my stock cap, instead I ordered a Japanese Honda OEM gas cap. It fits like a glove and I filled it up to where it would normally leak and after scooting back on the seat I gave it the beans and not a drop of gas came out

I think on my cap the seal was the problem, hence the o ring I put in it. But it wasn't enough to hold the seals shape. The Honda caps seal looks heavier and better made. it sure looks purty too! Nice chrome finish. I think that was the best $40 spent yet!

[herbie]

A comparison

[herbie]

I guess I have a real Chonda now!

[ChipToothy]

Nice solution buying a new cap. Wonder why the rest of us haven’t thought of that? I’ve had a few rounds of soaking gas out of the tank with the gas station paper towels ha! I want a whole different tank though.

[ChipToothy]

Originally Posted by goat67

Take a dremel with a cut off wheel to that cap.
In you picture the part that extends down can be cut off to just below the lock tabs.
I had the same problem until I did this.

Can you share a photo of yours modded?