Yes, you read the subject right, my et4 farts, which while amusing causes it to stall until it has "passed wind" and then runs till it needs to fart and stall again
I have a 2001 et4 125, this is a uk one so the evap hose system isnt there (you have no idea how many problem solving posts revolve around this)
When I first had it, it ran hot, from my previous vespa px knowledge, I presumed I had a bad fuel flow causing not enough lubrication and a hot engine. So I investigated the fuel tap to find the bloody thing was in fact stuck open partly and couldn't do its job.
I also noticed the carb maifold had a crack so both these items were changed for new.
For a few hundred miles it ran perfectly, then the bad starting and stalling started to happen. you'd hold the brake and press the electric start button, the bendix engaged and spun the variator but it wouldnt start till it farted! soon as it shot a blast of air out (from the airbox usually dislodging the under seat air hose) it would run great for a few miles until it stalled again whilst stopping for lights or a junction at which point made the engine sound like it was blowing bubbles as the air built up ready for another fart.
As soon as enough air builds up, my et4 stalls, some days you cant open the throttle more than 1/8 unless you want to stall, and when starting sounds like a co2 pistol firing a couple of times before it starts.
What on earth is causing this air build up? I cleaned my carb and jets, my airbox and air filter are clean and my tank has been cleaned out. Any ideas would be much appreciated, apologies for the waffle but I'm trying to give as much info as possible. Thanks in advance