Modern Vespa

I picked up some led bulbs from Vespa Motorsport that are plug & play for the front running/rear running/license plate spots. All seemed fine at first but now they flicker like a strobe light. The old bulbs work without this problem. Has anyone else experienced this? Any suggestions (besides using my old incandescents)?

My cheap ebay ones did that - looked like I was signaling a turn! Dangerous.
Installed better...and no issue for 2yrs running.
But, don't imagine they sold a cheap set.
O.S.

Check all the connections, and the sockets. LED's draw so little power that any little bit of corrosion will affect the voltage. And LED's react extremely quickly to voltage change, as opposed to incandescents, which are notably slow. Possibly you have a loose connection somewhere. If you know someone with an oscilloscope or high-end digital meter, be interesting to check the supply and see if your voltage regulator/rectifier is bleeding AC into the DC circuits. Incandescents don't care, LED's care greatly. If there is significant AC, there are ways of converting it and filtering it, but unless you want a short course in electronics, perhaps not worth the hassle.

My cheap Ebay LED running lights burned out quickly. I switched the power source for my running lights from AC to a key on DC circuit. The lights come on as soon as the key is on, but the LEDs are still bright 2 years later. And the chances of leaving the key on are quite a bit less with the bright running lights as a warning.

I played around with the three that are flickering and it doesn't seem like the problem is a loose or broken wire. Something I forgot to mention is that the three lights flickers with both the engine running as well as off. So probably nothing to do with the VR.

Yes I've had a few that failed like that. Just don't buy from that source again. Where possible I now go for the type having a metal sleeve, these have been more reliable so far. If you replace bulbs in the headlamp shell they can also overheat because they are too close to an always on headlamp bulb.

Had same problem of the converted LED's flickering with less than 20 hours use. I don't think they're rated for automotive since vibrations cause flickering, even at idle standing still. I put lithium grease on the contacts to no avail.
Got replacement LED bulbs that are now working for 70+ hours.

Yes, if the lights are flickering with only battery power, then the lights are at fault.

I've considered going to LED replacements. But it seems many never reach the expected lifespan, require modifications ( head lights and turn signal flashers, for example), and often fail to deliver on performance. Edison bulbs, in the other hand, are cheap, trouble free for the most part, and have acceptable lifespan.

I had a similar problem.......

LED headlights.....no way, back to a halogen

Most have been poor but my switchback turn signal run lights have been great but then again they came with an inline alloy box of trickery in the switchback unit.

LED's draw less from the battery and allow other battery operated components to operate i.e. hand warmers, under chassis lights, USB jack. LED are also brighter and whiter.