Water under the fuel filler cap

Last Updated on by Pat

Aprilia Futura – Water collection in the filler cap

When filling up after a heavy downpour (or washing the bike), it’s not unusual to open the filler cap only to see water swirl down into the tank.

This is because the top part of the tank is a cover that isn’t water tight and has a drain to let water escape. Except it gets blocked really easily, probably due to engine heat acting on its aluminium fittings, and stops the water from draining away. The end result is you get water in your petrol.

It takes 15 minutes to fix. First unbolt the front of the tank and hinge it upwards, using the prop rod you’ll find clipped to the underside of the seat.

The drain point is one of the two black hoses at the right (as you sit on the bike) rear of the tank.

Undo the clips on both hoses. then slide something small and thin into each aluminium pipe fitting – an Allen key did it for mine. The inner of the two fittings is usually the culprit.

Water will run out as you unblock it, but also any petrol that overflowed while filling.

If the water drains out when you remove the hose then check the hose for blockages where it sticks out under the bike.

Re-attach the two pipes and their clips, then re-fit and bolt down the tank and you’re done.