Problem with carburating – main jet and air filter

[rubymaxTopic starterBerichten: 73]

Hello,

I have a problem with proper adjustment of mixture gasoline -air for Piaggio SI. The set up is :

– original motor with no modifications on carter and cylinder
– carburator SHA 12/12
– air filter Polini
– Giannelli city power exhaust
– mono clutch – standard pulley 94mm

When I have changed my old rectangular – original Piaggio SI exhaust with new Giannelli city power and change original Piaggio air filter with six holes behind the metal mesh with Polini air filter I noticed that the motor is loose on acceleration but after obtaining the engine rpm It is very fast. First I have start with main jet 50 but I noticed lack of power in the bottom and when I have closed one of the three holes on the Polini air filter It is going better at the start (acceleration).I tried also with 54 main jet but the result is the same (lack of power on bottom) If I let open the all three holes on air filter Polini.
Is there a problem with too much air according to this Polini air filter which has obviusly more air flow then original one ?

Thanks for answers:)

[ciaoracer.dkBijdragerBerichten: 16]

Hello its almost certainly the Gianelli on a standard setup like yours a Sito Plus would be better.
Try the old Exhaust Again.

[joschi0815BijdragerBerichten: 82]

Just try the 12/12 Carburater with a dgm original Moped ( 40 – 45 kmh) Airfilter and a 50 mainjet. If you have a Moped ( Brommer) carter this Setup will run great with the Gianelli.

[ritzeBijdragerBerichten: 3421]

your pipe is good for a 50cc stock setup. normally youll have to fit a jet between 50 and 56 with a 12.12
check your sparkplug for color after 20 km, it has to have a dark brown color

De budget beun tjoener: geen geld is te duur of het werkt nog niet
Link naar Mijn collectie / Projecten.

[rubymaxTopic starterBerichten: 73]

ritze :
your pipe is good for a 50cc stock setup. normally youll have to fit a jet between 50 and 56 with a 12.12
check your sparkplug for color after 20 km, it has to have a dark brown color

what do you think about the Polini air filter in my set up? should I change it with the original piaggio one (DGM)

Best regards

[Noetiepoerker26DonateurBerichten: 469]

I would consider changing that, yes. Those tuning filters are (as far as I know) only used on quite powerful setups.

[ritzeBijdragerBerichten: 3421]

Some say… haha
i should run with the power filter but it will be tricky to get it right. You are changing pressures before and after the sprai bar. I always use power filters with big jetts. So just try to get it running with it. Otherwyse use a stock filter

De budget beun tjoener: geen geld is te duur of het werkt nog niet
Link naar Mijn collectie / Projecten.

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