Modern Vespa

Having looked at LED turn signals regarding the Euro Turn Signal/white-amber LED upgrade, I saw that at least one other MVer has encountered this problem, but with no solution (so far!)

I installed the Euro wiring adapter with no problems. Bought the V-LEDS and installed them, started the scooter, no white running lights. Grounded the right light to the frame, as suggested in the previous thread, and while the lights work fine when idling, when I rev the engine, the right light goes out, and the left light stays on. Back down to idle and the right light goes back on. In addition, the turn signals flash very quickly at idle, but flash at "normal" speed when I rev the scoot.

Not being all that electrically inclined, I'm at a loss on how to correct this.

Any guidance would be appreciated!

What I would do is run a temporary ground wire direct to the battery just to see if your Chassis ground is stable.

You could try a heatsink and go from there, you'll need one for each side and that will stop the double quick blinking from the LED upgrade.
I am not a mechanic but I would and have started there and had no further problems.
I also say make sure Everything is Grounded properly.
In most automotive electrical issues its the ground that's at fault.
Mega.