Modern Vespa

Hey y'all,

I'm trying to trouble shoot a 2022 GTV300.. HPE motor, 3000 miles and it seems like the starter motor is having a hard time getting thru the compression stroke? New Battery and connections are solid. I've bridged ground to ensure solid.

With a ratchet I can turn the motor over, and when pressing the starter button it turns the motor over, however, just once and then comes to a halt and disengages, not allowing it to start. Then the fuel pump cycle restarts and it will turn over slightly... again and again.

The starter relay seems to be working, the starter motor seems to be working? I can feel and hear compression. Spark is there. Fuel pump is delivering fuel to injector. I just can't get the motor to crank or turn over as it should. After 1 crank the starter disengages and the starting cycle restarts?

I'm curious as to if anyone else has run into this? Thank you for any help

My first thought is the battery can't handle the load. ie flat or buggered battery

That was my first thought as well but I've tried 3 batteries (I own a scooter shop and have them at my disposal) and all produced the same symptom. Every electrical component works and the starter does respond when triggered but comes to a halt and almost hisses like pressure is lost, then the cycle restarts

Do voltage drop tests from the battery terminals all the way through the wiring, including all junctions and relay terminals etc. Then you'll know where the power is being lost. If it shows that full pressure is really getting to the starter motor, then it might be that rarity, a shorted turn inside the starter motor, or a very poor connection to one of the brushes.

jump to the battery from a car battery. Negative on body, positive on terminal. If that doesn't turn it over, the starter is likely shot.
Take it out and do the poor man's bench test, where you push it into wood and see if it stops or has enough friction to make the wood burn.