Modern Vespa

I am the owner of Vespa GTS 300(2015 vespa super) living in Korea.

I tuned Polini 294cc and am currently experiencing the problem you experienced.

The idling of the motorcycle is incorrect.
When I get a signal while driving in the city center, the engine sometimes turns off.

The Vespa Mechanic is said to have been assembled accurately.

This is my current tuned history.

Polini 294 cc(with Polini ECU)
Original Head(porting tuned)
Open Airfilter tuned(KNN big airfilter)
PM tunning PM80 exhaust(No Catalytic Converter)
Polini Pully(17G)
Zelioni Pully wheel
Reveno Clutch set
Brembo GP4 RX Front caliper
Brembo p2 nikel Rear caliper
Earth brake hose(Front, Rear)
Zelioni aluminum wheel set
Marus Front hub
.
.
.


and I have Polini High Cam parts.

And I can buy Malossi V4 head.

I wonder if these two parts(polini cam+malossi head) are compatible with my Vespa(polini 294cc).
There is no one who tuned like this in Korea.

Help the owner of Vespa in the faraway country!

I'll be waiting for the reply.

Looks like a great build. I hope you can get it working properly. The problem sounds like it could be electrical.

as an experiment have you tried original air filter & box and also original exhaust?

have you cleaned the throttle body and also checked for air leaks in the intake?

checked / cleaned the fuel injector?

a photo of the tip of the sparkplug would be nice so we could judge if running rich or lean

Cam is compatible. Malossi head isn't. If you do install the Polini cam, you should install their valve springs too.

This is really cool and very impressive. As you said it must be an electrical issue. But before this check your Vespa thoroughly. Like air leaks, throttle body, air filter, and exhaust.

I tried to remove the polini ECU, but there was no difference. The idling was actually more unstable. It seems that VESPA ECU is already relying on polini ECU.

I asked for advice from a Korean mechanic. For two hours, Macanic tried to find an external factor, but he couldn't.

The mechanic explained that it was time to check the engine.
So, we decided to double check the mechanical part by installing polini highcam, malosi valve, and valve spring.
The mechanic explained that malosiv4 head can cause problems during installation. So I decided to install only the valve part.

Thank you for All reply.