Modern Vespa

Hi guy's So I bought this Gilera nexus 250 a few days ago. I have a problem where it randomly keeps cutting out at lights when I try to pull away. Starting it only happens if I hold the throttle open. I fitted a new battery yesterday as other posts mentioned this solved there're issue. I'm noticing that the volts drop to 12.2v on idal and rise slowly to 13.5. Also when riding with 1/4 throttle is soundslike the spark is braking up and misfires i have changed the spark plug Any help would be appreciated.

G'day mate.

Sounds like a problem with your valves. They require adjusting. Over time valves close on themselves squeezing the life out of the engine causing misfires, cutting out at traffic lights and poor performance. Not sure who you bought the scooter from but if it was from a dealer take it back. They should have done this prior to selling IMHO. If not. Check out scooterwest YouTube videos on valve adjustments and have a go yourself. Pretty easy to do yourself.

Good luck.

Tom.

how old is your nexus, is it fuel injected or carbed? and whats the mileage? I', the joys of diagnosis...

The first thing I'd do is replace both the spark plug and the spark plug cap. Both are cheap and your local dealer should have them in stock.

Sorry for the late reply. So I took it to a scooter shop and this is what the diagnostics showed. The shop told me that it could either be the lambda sensor or the throttle body. I found I guy braking a nexus 250ie so I bought the throttle body with both keys and the ignition setup. The problem is the same. I have a lambda sensor coming tomorrow if it doesn't work I don't know what to do next.
PO130
P0335
P0135
U1600

I've changed the plug will order a cap now

Hi Tom. I just watched the video it seems easy just need to dig out the feeler gauge! Also need to find out the settings for the 250.

Check for air leaks or cracks in the intake manifold and air filter pipe and the connection to the throttle body. Is the air filter clean?

Same as all the rest of the Leader and Quasar engine scoots:
Intake: 0.10mm (0.004in)
Exhaust:0.15mm (0.006in)

Nexus manuals, such as they are, are here:
https://manuals.wotmeworry.org.uk/Gilera/Gilera%20Nexus/

So the problem was a split inbetween the pump and filter inside the petrol tank

Well found! First time I've heard of that.