AntonLargiader
Active member
I have a 2014 RT in the shop that had a persistent gas smell on the test ride. Turned out the filler neck assembly was not sealing to the tank at the front. The top of the plastic tank is flat, and there's a rubber gasket on the bottom of the filler neck that seals to the tank. The front of the tank opening had a low spot that allowed a gap between the parts. I could see a rub mark there, as if something in the past had been pushing on that area so I bought a used tank, but the used tank is even worse in this way.
It looks like a bad design. The bolt circle is 4" diameter, but the gasket contacts a circle less than 2.5", so it's pushing down on unsupported plastic. There's nothing keeping that plastic flat enough to maintain a consistent seal against the lip of that rubber gasket (which is less than 1mm tall). Given the condition of the used tank I bought, I have to think that there are a lot of bikes out there with this issue. If you have a persistent gas smell from your wethead, it's easy enough to check this... make some sort of plug for the internal part of the filler neck with a tube in it, and lightly pressurize the tank by blowing into it. If it's leaking at the front, you will know.
This shows the depression between the threaded inserts at the front of the tank:
That low spot continues all the way back to the opening; you can see where the gasket touches. It's very easy to feel the low spot running a finger around it, but you can see it clearly with a straight edge also. There's no expectation that a 1mm tall rubber lip is going to seal this off.
As an interim repair, I have built this area up (on the original tank; the pictured one is the used one I bought) with a few coats of sealant but it may not prove to be a long-term solution.
I'm curious about other tanks out there; do they have this same low spot and leak, or are they OK?
It looks like a bad design. The bolt circle is 4" diameter, but the gasket contacts a circle less than 2.5", so it's pushing down on unsupported plastic. There's nothing keeping that plastic flat enough to maintain a consistent seal against the lip of that rubber gasket (which is less than 1mm tall). Given the condition of the used tank I bought, I have to think that there are a lot of bikes out there with this issue. If you have a persistent gas smell from your wethead, it's easy enough to check this... make some sort of plug for the internal part of the filler neck with a tube in it, and lightly pressurize the tank by blowing into it. If it's leaking at the front, you will know.
This shows the depression between the threaded inserts at the front of the tank:
That low spot continues all the way back to the opening; you can see where the gasket touches. It's very easy to feel the low spot running a finger around it, but you can see it clearly with a straight edge also. There's no expectation that a 1mm tall rubber lip is going to seal this off.
As an interim repair, I have built this area up (on the original tank; the pictured one is the used one I bought) with a few coats of sealant but it may not prove to be a long-term solution.
I'm curious about other tanks out there; do they have this same low spot and leak, or are they OK?
