Modern Vespa

Hi all,

New to this site but yep you guessed it, some advise wanted or helpful comments greatfully appreciated.
Here goes...I have a GS 160 MK1, problem is battery continues to discharge. I have changed the rectifier etc and apart from put in a new wiring loom (nightmare job by all accounts) I am at a loss as to why battery continues to discharge. If anyone has had a similar problem and sorted it I would like to know. I guess its a process of elimination. No way is a P range going into my scoot!

1) Good for you that you're keeping it original

2) it's probably the rectifier unit. The early ones were really dicey. If the rectifier is bad, it's not recharging your battery as the lights slowly drain the power.

3) You can find new ones on ebay. There's a seller there in california named "Scooter Salvage Shop" that unloads NOS GS parts like rectifiers on there.

Hi Eric,

New rectifier from a friend in France (available on ebayer for a good price!) has been fitted so its not the rectifier. Could be one of the coils on the stator plate? flywheel is demagnatised? or it could just be a drain in the circuit? arcing? Thanks for the response Eric, much appreciated.

Sure... could be a lot of those thing. Remagnetizing the flywheel is never a bad idea - it can't hurt, and it's relatively cheap.

It could also be a bad coil, yes. That's an easy thing to test, though, by simply measuring the voltage off the stator wire that runs to the rectifier in VAC when the engine is running. It's likely in the 6-9v range. As long as it's not putting out anything less than 5 you're probably ok.

Have you checked the quality of the wires ( particularly the insulation ) inside the engine, or coming off the stator? On a 45 year old bike, inside of a hot engine, this rubber breaks down and the wires short out to the engine over time.

Hi Eric,

Its frustrating what with the IOW round the corner, a friend has also mentioned the wiring generally over a period of time can cause the problem, even a bad earth can cause the battery to discharge. First point of call is to check the wiring for any defects I guess. I doubt if it could be coils/stator/flywheel as she starts very well and until the battery dies flys! Have you hasd a similar problem with your GS?

Well, it's funny you should ask about my bike.

The american models LACKED A BATTERY. Both my SS180 and GS160 were non-battery models, which made the wiring harnesses very simple, and similar to a VBB or early Sprint. They even use the same handlebar switches. ( unlike the non-US variety that have the round switch on them ).

Also weird, i was at Amerivespa this weekend where there must have been a dozen GS160's ...and most of them were the Euro-style, like yours, with the round light switch, key on the headset, and battery.

Mine is a LATE LATE 1962 GS160 - i think the serial # is in the last 300 of production. Mine is also a square tail Mk1, meaning it was 1 of the last 1811 GS160's made.

Eric,
Sounds like you got yourself a cool scoot over there, GS, white Max Meyer paint? grey or black Aquila seat? no doubt the GS is one seriuosly cool bike! totaly understand how much easier it is to have a non battery model, got a 68 gtr that just uses a 6 volt battery for lights, down side is you cant use it for long rides at night, riding by streetlight is kinda cool in London though.
As for the discharging, going to check wiring, change points and condenser, it might make a difference.

hey Eric you don't happen to have a spare GS160/SS180 kickstart lever in your shed or anything?

No, i don't... sorry.