Vespa 150 GL decelerates and backfires

Hi,

 

After 5 to 10m driving without any problems, my vespa starts to backfire and the acceleration isn't stable. It starts to stutter and decelerating. After a few minutes it's normal again, and then backfires and decelerates again... What could be the problem?

Hi, I think it has something to do with the ignition.

Had the same issue because timing was not proper adjusted.

But in your case if it happens only from time to time it could be also a loose contact or something like this.