Rain leaking into fuel tank from fuel cap (SYM XS125-K)

[CraddyMcPatty]

When rain hits the fuel cap on my SYM, it leaks right into the fuel tank, via 2 holes (I tried to illustrate where the leaks are) leading to water build up in my fuel tank (which is super uncool). Anybody know if I'm missing a seal or SYMs just come like that?

[jeffyjeff]

First thing: if that is indeed a photograph of your filler cap, two of the allen-head cap screws are visibly loose.

Secondly: there is typically an o-ring that seals the cap to the tank. It is designed to seal the tank so that the tank breathes through the evaporative emissions control system. If sealing properly, the o-ring seal will be water tight.
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History shows again and again how nature points out the folly of men - BOC

[Easy-X]

Some tanks also have a drainage system for petrol overspill and water. Maybe you have a pipe that's blocked?
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[stinkwheel]

As above, that's not the bit that seals, there should be an overflow pipe running from the area under your two blue circles to under the bike somewhere. That area is effectively an overflow catch and is outside the tank. The tank proper starts at the edge of the smaller hole under that cap where you stick the end of the pump, there should be a rubber seal which butts against that.

Again as above, if water is building up in the overflow area under the cap, the overflow hose is probably blocked.

Picture of a similar fuel cap off google images labelled for illustration purposes.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[BTTD]

I had this issue once. The drain pipe was blocked (blew it out with compressed air and a dead wasp came out the end) so the filler neck would hold rain water. When you opened the flap, the water would then then go into the tank.
Clear the drain hose and run some dry fuel additive to remove any water sitting at the bottom of your tank, or drain the tank.

[CraddyMcPatty]

[CraddyMcPatty]