Modern Vespa

My Vespa has stared cutting out every few minutes. I suppose it is fuel related as no engine management light and restarts after a minute or two. Battery replaced just in case it was that but problems persists. Any tips on what to check to narrow the problem down?

Very first thing - check the spark plug cap and HT lead. It's probably due for a new spark plug as well. The HT lead screws onto the cap, and that screw can corrode to nothing - also the spring inside the cap that holds it on the plug top corrodes and eventually disintegrates. New plug and cap are cheap enough to buy two of each now, and have a spare for next time.

Great, will try that first. I am not mechanically minded so assumed spark was only needed for initial start 😀

"Every few minutes"

is that every few minutes while riding?

while idling on the centre stand?

while the engine is cold vs warm?


Also, if it has a kill switch then toggle on/off about a couple of dozen times (seriously)

Whilst riding. It just cuts out completely after a couple of minutes, coast to a stop and then switch engine off and on again and away I go. Happened 5 or 6 times in a short 5 minute journey.

does it do it on the stand? test the permutations.

Changed spark plug and had a short ride and no cutting out! Hopefully problem solved but will give it a proper ride out at the weekend. Thank you!!!

Ok, went for a longer ride and same problem with cutting out. The bike won't start at all now and is completely dead. Checked the 6 fuses in the glovebox and they are fine. Battery has full charge 12.6 V so what do I check next??

I had that problem with my 2007 GTS250 - riding along, engine would cut out, stop and then restart - all o.k. until the next time. Took it to the dealer and it was the kill switch overheating for some reason. New switch, all o.k.

sorry for the stupi questions but I am a slow learner

I have now tried the IAWdaig software and it did show some stored faults that I cleared. I rode the bike and as usual it died after a few hundred metres as per usual. Re-ran IAWdiag hoping it would show the fault but sadly there was no new fault.

Does this make it more likely that I have a wiring fault somewhere?

Sorry if these are stupid questions but I am a complete novice

I attach the last report just in case it is useful.

@fungomerry this thread is for assistance with guzzidiag.

Where should I post it then? I am trying to keep it within my thread for my stalling bike rather than post up something new elsewhere 🤷‍♂️

Sorry, i misread. I thought you'd posted in a different one. Posting before caffeine is dumb.

You're correct to post it here.