Since no one is talking about microcars right now, what Yamaha moped do you have? I fixed my Puch last week, the air intake rubber sleeve had sliped off the carb mouth causing a week mixture and poor performance, refitted it and now goes like a rocket! Well 38mph anyway!! Did the Cold Turkey run on Tuesday, completed the course without wrecking the cabbage fields!
Yamaha QT 50. Girls moped really, ,looks it mostly!
I hit 27mph once, but thats top really.
I had the same problem with the rubber sleeve, but before that the wrost problem was when it only ran with choke *and* 2 fingers on the air filter hole (didnt work with filter on), leaving a small gap. Obviously couldnt really ride it! I made my own foam (old one was falling apart, was very thin, but seemed original, and had a couple of holes). My foam was a lot thicker, so wuld ghive it more suction, somore fuel goes past.
It never seems to go well the first minute it runs, but I have never ran it on the road (apasrt from the road between our big field and our house, since I have no license), maybe needs a good old run (out of the fields) to wear things back in place. When I got it (for free) it sat in a garage for a while, didnt run at all, needed a load of work to get it going.
Our Puch seems to go well, sometimes loses a bit of power, I jsut clean carb, and cl;ean exhaust (gets really dirty, even with correct fuel mixture)
JP