i have a vespa primavera 125...with a polini 130cc 6 transfers. I want to know if there are more better or have more power the polini with double instakes .
I want to change to have more power but i don´t want to pay 600€...there are someone more economic ??
now i have a p0lini 130 (iron) with a 24 carburator. with a polini exhaus ...direct intake ..and i want more power..i don.t know if change a polini 130 and install a malossi 136 or preserve the polini and instal a new cramshaft.
Okay, even with the sealing pad removed the full circle crank gets total in the way of the inlet, leaving you with a tiny gap for the mixture to get through - great for revs in neutral but no power at all.
Full circle cranks are designed for barrel reed induction.
So, either take the crank out, get it pressed apart and a (big) chamfer machined on it then rebuilt or open up the inlet hole into the mouth of the barrel spigot area. Machining the crank a better option.
like vespabestia said the crank is important, but important is also the feeling you want to have from your engine.
A malossi will give you more power, expecially higher on rpm, but not that much more. If you generally drive at normal speed and you need more "push" you are looking for more torque.
The rpm zone that you are targetting to have the feeling of beeing pushed is extremely important. You can have one engine with 30hp having less hp at 4500 then one having 20hp. This is where the power curve plays its important role.
Since for the limeted possibility of a small vespa engine, except if you are willing to do insane things, you cannot mount bigger barrel to push the cc.
It means that you are going to find the more power higher in the rpm zone. To get this you have for sure to use an expansion exhaust if not it would be completely useless.
Hi there, does anyone have any knowledge on a 54mm stroke full circle crank fitted with a polini 135 with packing plates and a 24mm reed valve crank case induction, I’ve got plenty of revs in neutral but stick it in gear and try to pull away the engine just dies. Wondering if the full circle crank needs to be chamfered to help gas, obviously I have opened up inlet and removed sealing pad. Could I have taken too much out, cheers in advance