Modern Vespa

Hi All,

My first post on the forum - I wonder if anyone can help?

I have a 2012 Vespa 125S with a problem. When riding the bike with the throttle closed for a while e.g. down a hill, the bike cuts out completely or refuses to rev beyond idle. If the ignition is turned on and off the bike is absolutely fine again which suggests an electrical issue to me. Otherwise running is problem-free - the bike is smooth and has power.

Does anyone have any suggestions?

Thanks in advance,

FBB

Uh-oh!

No-one got any ideas? Do I have a unique problem?

Bike only has 3300km on it so low miles.

Any thoughts would be welcome.

BTW, great forum! Been continuing to dig to see if anyone has similar issues and have come across some very interesting and funny threads!

FBB

Check the HT lead is firmly screwed into the spark plug cap, and that the cap is firmly on the plug itself - your symptoms match apart from the 'downhill' part - which I suspect is purely because then you're throttled off, which is the pertinent part.

And welcome to MV.

Thanks for this! It's definitely a "throttle off" issue. I was using the downhill part as an example of when it may typically happen. Rolling to a stop at a roundabout or junction is equally likely to produce the effect.

I've been riding around the problem today by keeping the throttle off-idle even when stopping; instead, using the brake against a slightly open throttle and that avoids the issue. Anyway, I'll definitely check both those things. I'll update the post with the results.

And thanks for the welcome!

FBB

OK. So I checked he HT lead and it seems to be securely attached. I DID notice that the "cloth" cover over the lead itself was chafed where it had been rubbing against some other wires further back down the lead. Thinking this could cause some interference I wrapped it in tin foil and duct tape.

No difference!

I notice the symptoms only happen when the engine is fully hot. I feel like I could avoid the issue if I could adjust the idle speed up a little but the idle screw (I assume it's where the throttle cables attach to the throttle body) is sealed.

Any thoughts anyone?

Thanks,

FBB