Tech tips please!

Hi. I’ve got a standard PX150E (apart from a siminini exhaust), and i’m doing a overhall on my engine bearings/seals etc i’ve just purchased a Malossi 166cc and a Polini 28mm rotarycarb,both are full kits from SIP. I was wondering if i would have to modify anything when putting these on?. Has anyone got any idea on what sort of gearing set up would best suit the new kit? T5 fourth maybe?. Any handy tips appreciated!. Marc:p

Hi Marc,

To get the full potential out the motor you would have to modify the casings/crankshaft. It depends what you want.
If you are going to the trouble of fitting a big carb then I guess that you do. The malossi kit instructions should give details of the
modifications to the casings/crank.
If its autolube you will need to blank off the drive hole as I don’t think the polini manifold covers it.
Make sure the carb is jetted properly or you could ruin the kit, big carbs can be a real pain to set up.
The standard gearing should give really good acceleration but will rev higher at top end. Upgearing with a gear kit or 200
gearing will give less revs at the top end[more relaxed cruising]and maybe a bit more speed but will probably give less acceleration, again it depends what you want.
The clutches can crack/explode, I used a 200 clutch on mine.

Taffspeed have info on tuning a PX with info on gearing on their

Hope this helps


Greetings Marc, May be you could also drop in a reed valve by malossi, it could increase 12 to 17 percent in HP , and one more thing , better convert your front brake to a dics brake by grimeca, sure it cost a bit, but safety has no price, right eveyone? [I)]