I’ve just receive my new PHBH 30 carb from SIP (Malossi kit complete), is the carb setup ok or do I have to modify it and how?

it will need jetting.
whats it going on?

Thank you, I’ll check up after the mounting, there’s no problem if the carb is not horizontal?

ok, do I have to change my crankshaft absolutely f I match the port of my cylinder and manifold or can I use the original one? If not what is the best choice?

Setup :

  • PX150E
  • Cylinder Malossi 166
  • Exhaust SIP Performance
  • Upgear kit Malossi 23/64
  • Carb Dell’Orto PHBH 30 with standard manifold
  • I plan to match the cylinder port and the manifold.

Tell me all, friends…;D

Ok thanks, is the original Piaggio gasket between the casing and the manifold ok or do I have to put a bigger one going longer (on the autolub which I do not use)?

Thanks a lot, Curare, it’s clear now!;D


the carb is set up but it doesn’t mean that its set up will be good.

The carb set up change according to the weather, your engine set up, exhaust etc…

The only way to know if it is ok is to try it and see.

Setting the carb. is not that difficult, but you have to follow a method.
First start from the iddle and try to have a regular trottle using the air screw and the opening screw valve… and moove up.
If you need more dettail ask.



the original gasket is perfect if you don’t enlarge the inlet of the crancase. If you do you have to match the manifold and cut a little the gasket. But I will do it only if you want to top tune your scooter, and if you already done everything else. cases porting, racing cranck…



if you keep rotative you don’t have to change your crankshaft, it will work with standard, but you won’t get full power.
Remember also to open the inlet on the compression plate as specified by Malossi.
But if you open the cranckcases and do all the work consider going reed, with malossi reed, are cheap and works well.

Malossi 166 is the most powerful kit for PX125-150, but it gives you the power on high rpm.
This kit likes reed a lot, as I have experienced by myself. About 15% more powe with Malossi reed.
It is not like the Polini 177 that is more on the torque side and doesn’t like to rev. high. For the polini, reed will give just smoother power spread but not not really that more power then rotative. (I am driving now a Polini 177 and reed, and other 3 vespa!).


you should be ok as the carb can be tilted up to 40 degrees;D

What do you mean buy „open the inlet on the compression plate as specified by Malossi.“? Can you explain as I don’t understand?
Is it true that I will lose idle if I use a anther cranckshaft and which one can I buy?[:D]


the inlet port is the hole in the crankcase where get in the fuel.
The inlet port has two faces. The outside face is where it is connected the manifold and the carb.
the inside part is the part that opens where the crankshaft is.
You can open the „outside“ part of the inlet port to match your manifold.
Then you want to open the „inside“ face. Here you have to be careful. You have to work lengthwise to alter timing (follow the mesure malossi gives about 2cm each side but I remember there is a part you have to open more, just have a look at their net site)
The thing you have to be careful is not to enlarge thewidth of the inlet port (crankshaft side). Bigger then 1mm and you’ll make the inlet port wider than the crank web that seals it. It will stay always open. This means that fuel can get in at all the times and not via the inlet port timing…

For the crankshaft: a crankshaft that has the timing altered, means it let the inlet port open longer, will effect your iddle and power at low rpm, but will also improve power at high rpm and that is what your kit needs since it will develop full power at higher rpm then Polini 177.

You could use Mazzucchelli race they are quite cheap and reliable, or a worb5 fine balanced that is based on Mazzucchelli.

This is if you decide to stay rotative… if you go reed is another story…