Vespa PX motor mit Malossi 210cc

Hello,i am Pascal from Belgium and i drive a T5 with a PX motor. The motor is equipped with a Malossi 210cc kit,with in first stage a standard Piaggio head 200cc.After a few weeks,i mounted a Pinasco 208cc.head.Last week i burned a hole in my piston......Spark plug was an Ngk B8 long thread. There is also another exhaust mounted since a few (+/- 1500km) kilometers (a JL lefthand).With placement of the exhaust i also putted an 10 numbers higher main jet.The spark plug was white-lightgray.Now there is so much choice at sip webshop,that i don't understand the different "class" in these pistons (A,O,H,.......).My piston is equipped with 2 rings.I must tell also that i was at a filmset,wich means that the motor turned a lot of time at stationary rpm's.

Can somebody help me please? I don't know wich type to order (i don't find part numbers on cylinder or piston).

Kind regards,


Hello Pascal,

clean the top of your old Piston, then you normally find the type (A, B, C, etc) of the Piston. A Problem could be the hole, if it is maybe exactly at the Position, at which the Type is...

Why did you use a Pinasco Head? Better will be the Head from "MMW" for Malossi (but have a look at your crankshaft ... 57mm or 60mm???)

I mean that your main Jet was definetly to low... use about 140 at a SI 24/24... White-lightgray is not good... I always use the Spark Plug from Bosch (W3CC) with Malossi...

Maybe this will help you.

Good Luck



Hello Norre,

I cleaned up the head of my piston,but unfortunatly.......the hole in the piston was there.....I asked a belgian mechanic,and he told me that the piston type is marked on the cylinder.And i found an "A" marked right on.

So,the problem is solved ! Thanks.