Modern Vespa

If your slider is neither influencing nor visible at the orgy, you're definitely doing it wrong.

Ray - interesting stuff you are working on.
Looks totally worth it's own thread!

Full load orgie = WOT
There are many roads that lead to Rome = Lots of ways to skin a cat.

You'll find MANY similarities between the SI and the Weber!
SI tuning = Weber tuning.

I'm getting the "feeling" I've shifted power lower in the rev range with the sleeve, but I could be very wrong since I'm still jetting the new setup. CHT is down 35-40 degrees up 800ft 4th gear climbs. Two hour ride never got over 244. I asked Andreas for suggestions based on my bike and he said first thing is the sleeve

More SI info here. A recent blog from Andre (SIP).
Scroll down and watch his video with Andreas. There's an English version I can't find now. The translated video is hilarious.

https://www.sip-scootershop.com/en/blog/the-dellorto-si-carburettor-for-vespa_p371

Thanks Ray very interested in increasing power in the lower rev range as you can imagine.

Is the sleeve something that narrows the throat of the carb, increasing the air velocity and thus improving atomisation at lower revs? and thus improving torque? or am I way off base?

Ive always felt there is a need for a bullpark jet check list based on REAL users experiences versus the setup they have. For example, many 166/177 kit users I know, including myself or I read about on here end up around a 140 BE5 and some maxed jet up to 125. Be good to have a whole range of individuals setups, the scoot they are using, exhaust, carb etc to at least get somebody started for dialling in their carbs. Decent genuine Delorto jets are pricy these days, the amount of money ive spent on air correctors, mixers and mains is stupid trying to get something right, got all manners of jets in bags at home. Even found a 170 AC, what the hell is that from?

There are some things that are generally given. e.g. a standard px125, upjet 4 for a road 2.0 and 1 or 2 for drilled filter. Pretty much the same for a polini box. Maybe we could start a master list?

Theres this.
SI jetting calculator .. useless exercise of boredom

And where is the accessible version? Thats a really good thing.

Its not accessible as he states in the post, but i found the info interesting and useful and my jetting was /is pretty close to whats in the tables.

Hoping someone else will find this with a Jetting Question Aghh search.
These guys are wild.

It was.
Sort out that suspected air-leak so you can move forward vs sideways!
If you don't want to spring for a tester, at least look at the gaskets under your carb and box gaskets for the usual suspects' trails.
An engine with a sudden air leak will sound like it's hunting for fuel on a jetted bike.

Made up a leak tester ( details on my other thread sidecar i.d build and ongoing 'adjustments' (Page 2) and found an easy/stupid leak on the carb, bolt had loosened.
so back to fine tuning the settings.
Where do you get those bits Ray? sleeve, slide and modded atomisers

Great.

https://www.sip-scootershop.com/en/search/lemarxon

Thanks Ray

Jetting has definitely been one of the hardest parts of getting an engine going. Being able to hear/feel the difference between rich and lean was the first hurdle. I still can't do it consistently. The most helpful thing has been working down from a main jet that is really obviously too rich. At that point, there's only one direction to go. As you work down, the point where it gets better is really noticeable.

Above a 125 main jet, there are fewer jets commonly available and the jumps between jets get bigger, so going with a lower number air corrector can help you stay in the range where the jumps are a lot smaller.

I can't imagine you not benefiting with the sleeve, pulling a side car.

Keep in mind this a system.
I'm rolling with a (measured) 127/X234/150 ac. 52/140 pilot*, idk how many turns out on the mixture screw -- you have to play with that on the road.
LM-M slide.
*Only slightly better than a 50-55/160.

I was wondering about idle jet selection too…whether it's like the main with choosing as rich as possible as long as it runs well. Right now, it's running great with a 50/140, but if I can go richer, should I?

If I'm going for a longer ride, I end up adjusting the screws after the engine is warmed up. Maybe a little on the mixture screw if it's going to be faster.

Can I ask what made you select those components i.e the slide and the atomiser

That's what Andreas recommended I try based on my bike's setup.
Only have the medium $lide.

I haven't tried the XX34 atomizer. The X234 with the sleeve and M slider is working very well here on my twisty steep hill climber, which I'm imagining would do you well pulling a sidecar.

These bits are not a gimmick.

Thank you for that.

Here's another sidecar setup using the 22mm sleeve.
"Pulls like a buffalo. Almost like an automatic."

HLKD = AC
MR = atomizer
HD = main jet
NLKD = idle jet air corrector size
ND = idle fuel jet size
Schieber = slide
LLG = turns out on the mixture screw

https://www.facebook.com/photo/?fbid=573611694938169&set=pb.100068680308845.-2207520000.