The Idle Rich?

[Doom Patrol]

This may be quite a simple one for those in the know. Lambretta 200, standard barrel and 20mm carb but with a SITO Ancillotti I inherited. Main jet I would say is about right, and anyway I can't recall what it is offhand. But, what concerns me is the idle jet. You just know when you start it that it's not firing cleanly and when you pull away it's what I can only liken to as machine gunning. Should be a 48, but I was using a 50 and it was awful to ride when it was cold without giving it lots of throttle. I've dropped back to a 48 now, but in view of the exhaust I don't know how advisable that it. The problem is still there anyway. It does improve after a bit of a run though, but that's not the point. To my layman's mind it seems rich, but it's on the standard idle jet already. So I don't quite get it. Any advice would be gratefully received.

[rog60]

I believe that (according to the manuals for carb specs) that a 45 idle is the 'standard' for 18/20/22ml carbs and is what I use (48/50 would probably be for 175/186 kits

[Doom Patrol]

I think the 45 pilot jet was only for the GP200 and the 22mm carb. It is a 200, but not a GP.

[rog60]

To clarify.....I use a45 jet with good results on a SIL 200 with 42mm clubman. Only TV/sx200 used 48 jets and Li125 42 idle all the rest used 45 idle why not try and see .adjust idle mix by using the mixture screw (out to weaken, in to richen)

[paulski]

To clarify.....I use a45 jet with good results on a SIL 200 with 42mm clubman. Only TV/sx200 used 48 jets and Li125 42 idle all the rest used 45 idle why not try and see .adjust idle mix by using the mixture screw (out to weaken, in to richen)

lammy 20mm carb mixture screw is out to richen/in to weaken isn't it???

[rog60]

Yes........OOps