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...

