Modern Vespa

I got this message from my brother, who I sold one of 2016 300 GTS's, while he was at the Floyd Music Festival.

Ran fine when I took it for run last Saturday. We got up to Floyd today and no power, not running smooth and barely pull up small incline. Any thoughts? No internet in this cow pasture.

We discussed it and covered all the usual problems, but due to the continual ran and deep mud he decided he would leave until he got home.

On the way home he stopped a Josh's shop in Mebane, NC a great mechanic. To our surprise the problem was the kill switch. My brother used it occasionally and evidently it was breaking the connection just enough to make the scooter run rough. Josh, not having a spare on hand, took the switch apart, cleaned and reassembled it.

I have never heard of the kill switch operating like this. And, if you are in NC and need a great scooter mechanic Josh is the one. It is the Josh and the Scooter Garage and though google maps says it is "temporally closed" it is open and doing business


Josh after fixing switch checking everything over.

I have an intermittent stalling problem with my Stella. I mentioned it here on the forum and another user almost immediately mentioned "kill switch". I don't think that's the issue with my bike, but the fact that it was mentioned so quickly is very telling.

I missed that one. Just recall all the ones of not starting but not of intermittent running problems. That said it must be more frequent than I am aware of since that's what Josh went for.

I am having a problem with the Vespa failing to start at times. Everything is fine, battery is fine, no fuses blown, the relay is fine. I toggle the kill switch and sometimes it will fix the problem and other times it wont.
For now I have not bothered to open it up and clean the contacts etc. I plan to do that end of the month.
But it is weird, I have left it parked at places and then taken the subway back home, gone back the next day it starts up fine.
I am guessing it is the kill switch that is misbehaving and cleaning it may help. Scooter isn't running rough when it is running it is perfectly fine.

I park outside. My Piaggio MP3 would have problems with my lowbeam light not working so I noticed the highbeams wouldn't work either. In my frustration I rocked the very stiff switch a few times. It started working correctly after that.
So I have made a habit now of rocking all the switches once in a while even in my car and in my house. I guess everything needs exercise in this world. You are lucky to find such an aware and talented mechanic to identify the cause and repair the kill switch.

Last edited by Bigdaddy808 on Wed Aug 03, 2022 7:35 am; edited 1 time in total

I do the same with any type of rocker switch.

Good to know.

if you ever pull one of these switches apart be very careful. there is a tiny ball bearing and a tiny spring, both easy to loose. (I pulled apart both the kill and asr switches on my supertech as they were a bit sticky)

Thanks for that tip..
After cleaning the switch with something like rubbing alcohol or brake cleaner, do any of you use die-electric grease to keep the contacts working when moisture interferes.

You always should - corrosion can happen just with dissimilar metals touching.

I'll add - it seems it's only in NA that the MSF courses teach that you should use the kill-switch to turn the engine off. Elsewhere (including Advanced Motorcyclist training in the UK) you are advised to never use the kill-switch except in an emergency, and to always use the ignition key instead for daily use.

The MSF say this is to teach muscle memory so that in the event of an actual emergency you'll know what to do. This does wear out the switch - this *has* caused problems, often reported on MV - like this thread!

The RoTW teaches you to use the key so you don't forget to both turn it off (headlights have been wrecked on older models, batteries have been flattened, etc...) and take it out (security). Also, the kill-switch, being always unmolested, will definitely turn off the bike if and when eventually used.

I never use the kill switch to turn off the engine. When I am opening the seat sometimes it will sometimes knock the switch into a half ass off position.

I would clean it with contact cleaner specifically made for electronics and then load it up with dielectric grease. Honestly, I guess this is a consideration to have a kill switch on a scooter which I never thought about. On a vintage or motorcycle I would be more likely to just pull in the clutch.