Modern Vespa

I've experienced an odd reaction from my 2016 Sprint 150 on several occasions. My search of the forum did not come up with any similar occurrences.

I live in the Sierra Nevada foothills. When riding to town, I can coast long distances without having to use the accelerator. When my coast starts to slow below 35mph or so I'll give the accelerator a slight twist. When doing so, occasionally the rear tire briefly bites/skids as if I'm downshifting into a lower gear.

Has anyone else experienced this and is it normal?

It's normal. As you've coasted downhill with the throttle off, the clutch has become disengaged. When you give it a twist, the variator spins up, grabs the belt which spins the clutch which engages again.

Unless you get the new throttle position exactly right, the engine speed and transmission gearing won't be the same as the rear wheel speed - a 'lurch' will be felt as they syncronise rather rapidly. You feel somewhat the same thing in a car with manual gears if you don't match engine speed appropriately on a downshift - albeit mitigated by syncromesh.

What Jim said. I have seen this on my LX. It does freak you out the first time it happens.

Thanks folks! I was hoping something like that was the case.