Li S3 150cc standard carb technical question

[Chewyboy]

Hi everyone,
Nerdy techy question.
As a diesel fuel injection engineer in a previous life, who has almost finished restoring an Li S3 125cc Lambretta, I have the following question. Am I right in assuming the choke jet and the main jet get their fuel supply from the float bowl through the holes in the lower end of the screws? If so, where does the pilot jet get its fuel supply from as this doesn't have any holes at the bowl end?
Thanks in anticipation
Paul

[Nigel. S]

Via the main jet through a connecting channel.

IMG_0703.JPG

[Chewyboy]

Thanks Nigel
That's the cross section I have been searching the web for without success. Shows how important that connecting port is. Pilot jet and pilot jet hole could be clear but if connecting port is blocked that would spell trouble. Where are the pictures from would love to get a copy of that book.
Paul

[Nigel. S]

This is the book picture is from. It deals with LD, series 2 and has only a supplement for slimstyle. It doesn't get much use other than flicking through it for enjoyment as the modern writings on lambrettas have the benefit of 50 yrs of lambretta usage/wear and tear to draw on. However, it has some great period pics, engineers wearing proper trousers and shiney shoes, no adidas sambas and jeans and some nice adverts. And occasionally it can answer a question with a cross-section of something or other

[Chewyboy]

Cheers Nigel

[EddieStone]

Mmmm! Does that mean if you increase the size of the main jet, it increases the flow to the pilot jet? i.e. the pilot jet is related to the size of the main jet?

[Tractorman]

You may increase the flow too it but the flow through it is governed by the orifice size of the pilot jet.