Modern Vespa

I have a new 310 Super Sport. Only a couple of rides so far, (66 miles).
My comment and question is this: at idle you can feel the "lumpiness" of the engine. It smooths out as soon as you raise the rpm and ride away. It is not a concern, it feels kind of good actually, but I am wondering if other owners have a similar observation. I have owned other big singles, 500, 650, 690 and none have felt this lumpy at idle.
The scooter runs great, smooth, and I am loving it. Interested in what others are experiencing and willing to share with comments.

Have you had a GTS before? My 310 feels pretty similar to the way my 300 felt.

No. I have a 2023 Primavera 150 and I remember it feeling a little rough at idle too for such a small engine. I think it has smoothed out a bit, has 2,900 miles on it. As for the 310, I do not think of it as an issue, just a characteristic of the engine / frame integration, and a new engine getting all of the moving parts used to playing together. I kind of like it actually. The exhaust is so quiet the lumpiness lets you know the engine is running.

When you say rough at idle, is that with you sitting on it, possibly holding the rear brake? If so, this is a known characteristic of scooters with the engine and transmission as unsprung weight.
FAQ: Why does the engine sound different with the brakes on?

I think it's as matter of perspective. I had ridden my Kawasaki to the parking area before I climbed on one. It felt about the same as any scooter I had ridden before at idle, kind of buzzy. It smoothed out once in motion.

Yeah. As Jim says the engine vibrates depending on how you hold the brakes... this is the 300 but the same applies... watch at 4.35

I used to have a Scarabeo 500 and the lumpyness is why I got rid of it, very unpleasant. In hindsight lighter rollers would have made it better, it was just a question of the transmission engaging at too low rpm. I test rode the 310 and didn't notice any lumpyness. Same for the BV400.

I don't think the lumpinesses variously being described here are the same thing.

And lumpiness at idle being potentially solved by different rollers does not make sense to my understanding of the symptoms, or to my understanding of rollers.

Who spends time contemplating the value of the Scarabeo 500 at idle anyway? Not me.

The '20 GTS300 HPE I owned was remarkably 'lumpy' at idle, then smoothed out nicely the instant it was underway.

As others have noted, it was most pronounced while holding the rear brake.

It never bothered me.

Took the scooter out for a 35 mile ride today. The lumpiness at idle occurs on or off the center stand, hands off the bars, (no brakes applied). When I apply either brake there is no noticable change in the felt phenomenon. With the scooter on the stand at idle, when applying the rear brake there is a slight heard increase in engine RPM. I think that is normal due to stopping the rear wheel rotation.
So my thoughts at this point are, it is what it is, and it does what it does, and I love riding it! What a great scooter!

With less than 100 miles on a brand new engine, I think you risk being harsh on its true potential. The engine is bedding in, all the friction surfaces are smoothing off. The ECU will be learning how the bike is performing air temps loads fuel types.

I suggest you wait until you are at 300-450 miles then see if its still an issue. If it is you can advise your dealer and they can check for any software updates at the first service.

Yes, I agree. Did not intend to sound harsh about the scooter, just trying to learn its characteristics. I am quite pleased with it so far and am looking forward to many enjoyable miles of riding.
Thanks for all the inputs.

There's no actual increase in RPM - just a change in the harmonics because the rear suspension has been locked. It's a mis-translation by the human brain.

That makes sense. Thank you for explaining it. 👍