Modern Vespa

Purchased a new 75th Anniversary Vespa GTS300 Supertech, it was meant to be for my girlfriend but she is still to pass her A2 meaning I am now a scooter isn't. When I first picked up the Vespa at the end of a ride it made a noise like a boiling kettle letting off steam. I looked online and it sounded like the overfill when I had refuelled. I carefully ran it in but at under 500 miles the dash spanner came on whilst doing a first two up ride. I went to the local dealer in Canterbury who are a Vespa dealer and are what I would call a proper old school motorbike shop. The Vespa was due a first service so two birds with one stone, the fault was a sensor that was something to do with the water pump. I think the sensor sends false data and the cooling system tries to react. Anyway sensor changed under warranty now at just under 1000 miles and the noise is back. When I stop the noise an intermittent noise like a kettle that briefly boils and let's the excess steam off then goes back to silence. I normally ride a Ducati desert sled and don't have any issues with water related noises (as air cooled v-twin), nor any other noises when I park up. The Supertech is a great ride and you can throw it into the corners. There is a flat spot when I throttle off where the engine feels like it is hunting, but I have just out this down to it being something in the ECU. Hopefully some Vespa genius can tell me the sensor is a known problem and hope that it is just a bad batch? Anyway that's my first post done!

Welcome to Modern Vespa. The issue you are describing sounds like the radiator fan swiching on and off. When the water cooled system exceeds a certain temperature the fan kicks in automatically. It normally happens when the scooter is stood for any length of time like in conjested traffic. I have not heard anything thing about a bad batch of temperature sensors, perhaps the replacement your dealer fitted will cure the problem, if it is indeed a problem.

Yes I agree, my fan came on for the first time yesterday which sounds exactly what you describe. Luckily I have been riding modern Triumph motorcycles for the last few years so knew what it was or like you I would of wondered what on earth that noise was.

Welcome to the forum.

Thanks, the lack of the spanner must mean it is the fan rather than another sensor. Happy days then.

the spanner is not a fault indicator. it is a reminder that you are due for a service.