Modern Vespa

Hi all,

So my battery wouldn't hold a charge so i bought a new battery but i still have the same problem, i'll jump it, go for a spin, turn it off and 5 minutes later it won't start? I'm guessing now it ain't the battery but those anyone have any idea what it might be?

Gail

Dd it get a full charge before you started using it? If it didn't have a good initial charge and it's been discharged too low, it may not ever hold a charge.

Are the terminal connections clean and tight? Easy to check.

Do you have a multimeter (voltmeter), in order to test the battery and charging system? Measure the DC voltage at the battery, while the scooter is off and while it's running.

Certainly does sound like a charging problem rather than a battery problem. Connect a multimeter across the battery terminals, set to DC V. You should see something like 13.5-14.5V with the engine running. If it is around 12.5V or less then the charging system isn't working, which can be a fried alternator or a failed regulator/rectifier, assuming the wiring is all in good working order and all connections are clean/tight.

Can you elaborate more what happens when it won't start? It turns over and tries to start, but won't go? Or it just sits there dead?

Anything going on with the immobilizer light?

You said it will start if you jump it - like from a car battery and jumper cables? What if you charge the battery, then will it start again?

I'd expect a charged up battery to start the bike several times, even if the bike wasn't charging it in between. Maybe there's a short that's rapidly draining the battery but somehow not causing a fuse to blow.

how did you prepare the new battery?

I had a burnt-out stator on my Honda Silverwing and rode that with just a fully charged battery for a few months (while I waited for the Slow Boat from China to arrive with my parts). On that bike (with fuel injection and two cylinders), I could start the bike and ride for 30-40 minutes before running out of usable electricty and needing to recharge. The warning sign was the dash going crazy with many random warning lights.