Fuel tank exploding. 2019 Fx

[DanSVHO]

Yes, the bottle was dry before the ride and about 1/2 hour into the ride I started smelling fuel and then saw/felt it in my right footwell. The pressure is so great, that it is filling that bottle and overflowing at the nipple under the cup holder starboard side cowling.

Did you empty the small accumulator bottle inline with the vent hose? Mounted just forward of the seat opening, I think.

Did you also purge (compressed air flow) all the vent hoses of liquid fuel before installing the new check valve?

If the small bottle was empty before you began riding, it would have to become filled with expelled fuel before any could exit the upper vent and flow down the outside of the upper deck. Is the bottle again filled with fuel?

[K447]

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Did you also purge (compressed air flow) all the vent hoses of liquid fuel before installing the new check valve?

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... The pressure is so great, that it is filling that bottle and overflowing at the nipple under the cup holder starboard side cowling.

The pressure relief valve allows air flow into and out of the fuel tank. That is normal operation as needed to compensate for air pressure changes inside the fuel tank.

So it is normal for air to flow through the vent hoses between that check valve and the hull exterior. Those vent hoses droop down very low inside the hull and are quite long. If there was liquid fuel laying inside those hoses it would not be unexpected for that trapped fuel to flow upwards to the exterior hull vent fitting, and from there to dribble out.

[DanSVHO]

I’ll clear the lines and recheck but the line are high up near the steering column. What would prevent this from happening in the future if it’s normal?

The pressure relief valve allows air flow into and out of the fuel tank. That is normal operation as needed to compensate for air pressure changes inside the fuel tank.

So it is normal for air to flow through the vent hoses between that check valve and the hull exterior. Those vent hoses droop down very low inside the hull and are quite long. If there was liquid fuel laying inside those hoses it would not be unexpected for that trapped fuel to flow upwards to the exterior hull vent fitting, and from there to dribble out.

[K447]

I’ll clear the lines and recheck but the line are high up near the steering column. What would prevent this from happening in the future if it’s normal?

The vent lines loop up and then droop down beside the fuel tank. At least they do on my own Yamaha and others I have looked at.

I would expect once the vent hoses are clear of liquid fuel that there would be no further troubles with gasoline dribbling out of the topside vent

[DanSVHO]

ill give it a try thanks for your help.!

The vent lines loop up and then droop down beside the fuel tank. At least they do on my own Yamaha and others I have looked at.

I would expect once the vent hoses are clear of liquid fuel that there would be no further troubles with gasoline dribbling out of the topside vent