Two-stroke carburetor cleaning and rebuilding
Lately my PX has been having a tough time starting, even warm, with more than a few kicks and the choke full-out to get the beast purring. There are a number of possible reasons for this, but a typical culprit is the carburetor.
With half of the carburetor’s job being to clean crap from the air and fuel before they mix, it’s a place that needs to be inspected from time to time for crud build up and with a 25 year old gas tank on the bike, and after a winter of storage (even with fuel stabilizer in the tank) there’s a good chance that the carburetor jets are gummed up or the filters are crudded up.
Fortunately, cleaning the carb is a relatively easy task, particularly when there are fantastic guides out there on the web for vintage scooters:
In my case, with a large-frame P-series, as always, Richard Hoar’s excellent go-to resource VespaMaintenance.com provides the answer. Richard has a step-by-step article on carburetor cleaning and rebuilding with excellent detailed photos every step of the way.
For Vespa small frames, there’s really only one site you need to know on the web: Niall King’s Vespa Small Frames site which contains a wealth of fantastic smallie maintenance, including a step-by-step carburetor rebuild. Like Richard, Niall makes our lives easier with a full photographic step-by-step of the process.
When it comes to Lammys, my go to site is the Lambretta Club of Great Britain. The Brits frankly just have the knowledge-edge on these scoots compared to us Yankees, with seemingly a Series III sitting in every other garden shed.
Again, the LCGB has a nicely broken down carb inspection, cleaning and rebuild with photographs along the way.
I did get a chance to take a look inside the carb this weekend, in part because minutes before my bike stalled at a light and took some serious kicking to get it back running. The fuel filter was clean and the jets looked pretty good, but I ran a thin guitar string through them (an old scooterist’s trick) to clean them out. I also remove the air filter and cleaned it in fresh gasoline. The whole thing took less than half-an-hour and now the bike starts on the first or second kick. Much improved.