The Citycom has a pipe hanging down near the centre stand with a plug and spring-type clip attached to it.
I quite often (maybe every month or so) release the bung and a white creamy fluid (<2" in the tube) drops out that smells strongly of petrol. However it is not flammable.
I've read that other Citycom owners have removed them, so I'd removed mine today but I cant help wondering if it was there for a good reason.
Is it plugged by the manufacturer as (just) a way for service techs to tell how much 'blowback' (?) there is in the new engine, or is it there to create some kind of vacuum?
I've searched the Citycom forums but I cant find any follow-ups that explain the benefit of removing it - except not getting smelly gunk on your hand and driveway!

It might be psychological but the Scoot doesn't seem quite so quick-off-the-mark now either...

Thanks in advance for your comments.

Could be part of an SAS (secondary air system) so if you've lost a bit of performance it's probably just the ECU relearning the new settings.

It'll be the air filtercannister drain from the crankcase vent pipe.
Keep it capped or air will be drawn in that isn't filtered. It should be drained at each service and probably flushed out when the filter element is replaced.