Polini 221 and 60 crank problem

Im wondering if someone can help me with my renovated 200 e motor.

It has a polini 221, 60 mm polini crank and vespatronic with a 26 mm si carb and sip road. I have set it at 19 mm and used the orginal head gasket that follows the kit. (big sqich!) The motor starts up on first kick but runs uneven and "splutters" for main jet i have tried a 128 and a 132 with no noticeable difference. I have road it and the splutters persist but otherwise runs great with lots of power. Since its a new build i haven't run it above 70 kmh but the feel i get is that it goes better on higher revs. A friend that's loads better at this told me that he thought it was gas following the exhaust out...? I have included a short video with the sound of the motor, or go to  Here !

Any thoughts? please write here or mail me directly at [email protected]


the inlet timing of the Polini crank is too long, your engine has as serieus case of blowback. This crank works better with a longer inlet track, the Si carbs are not suitable for these cranks.


I think that the splutters problem derives from the float chamber cover; your engine need a lot of fuel, so you have to use this one: