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@shipscat avatar
UTC

Hooked
vespa 125 vnb1t
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Location: antibes , france
 
Hooked
@shipscat avatar
vespa 125 vnb1t
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Location: antibes , france
UTC quote
hello peeps not been here in ages found a youtube video with some "clearer"
info on the devils work that is the dellorto si the clip is in Italian but can be youtube auto translated ish
www.youtube.com/watch?v=-t1wiE637JM&t=366s

take care and stay safe
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Molto Verboso
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Location: Los Angeles
 
Molto Verboso
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UTC quote
Re: si carburetor
shipscat wrote:
hello peeps not been here in ages found a youtube video with some "clearer"
info on the devils work that is the dellorto si the clip is in Italian but can be youtube auto translated ish
www.youtube.com/watch?v=-t1wiE637JM&t=366s

take care and stay safe
The SI carb in a stock setup is a like a juggler juggling three tennis balls. Perfect performance, but kinda lame, right?
We throw in an exhaust it wasn't engineered for. Now the carb is juggling two tennis balls and a bowling pin.
We kit the engine, expecting the SI carb now to juggle a tennis ball, a bowling pin, and a chainsaw.
@ray8 avatar
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Molto Verboso
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Molto Verboso
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UTC quote
Was so looking forward to the SIP carb tutorial that recently came out.
Barely a mention of the SI!
Oh well..
UTC

Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Location: London UK
 
Jet Eye Master
PX221 MHR, O tuned PX200, PX125 and some motorbikes
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Location: London UK
UTC quote
I really hope SIP continue these tutorials. Great information, just not enough of it. 20 minutes on carbs could have been 2 hours and still not covered 10% of the subject.

SI carbs are way more complex than they seem. Probably more information about them on here than anywhere else......in the world. If only the search function worked better people could actually find it.
UTC

Addicted
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Location: Planet Earth
 
Addicted
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Location: Planet Earth
UTC quote
Re: si carburetor
Ray8 wrote:
shipscat wrote:
hello peeps not been here in ages found a youtube video with some "clearer"
info on the devils work that is the dellorto si the clip is in Italian but can be youtube auto translated ish
www.youtube.com/watch?v=-t1wiE637JM&t=366s

take care and stay safe
The SI carb in a stock setup is a like a juggler juggling three tennis balls. Perfect performance, but kinda lame, right?
We throw in an exhaust it wasn't engineered for. Now the carb is juggling two tennis balls and a bowling pin.
We kit the engine, expecting the SI carb now to juggle a tennis ball, a bowling pin, and a chainsaw.
Amen to that, spot on analogy.
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UTC

Not So Moderator
VNB VSC VMA VSX - o9c vbc vmb
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Location: Hustletown, TX
 
Not So Moderator
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UTC quote
Quote:
Probably more information about them on here than anywhere else......in the world. If only the search function worked better people could actually find it.
True true
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UTC

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
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bodgemaster
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63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
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UTC quote
Jack221 wrote:
I really hope SIP continue these tutorials. Great information, just not enough of it. 20 minutes on carbs could have been 2 hours and still not covered 10% of the subject.

SI carbs are way more complex than they seem. Probably more information about them on here than anywhere else......in the world. If only the search function worked better people could actually find it.
Jack, this thread would be a perfect place for you to contribute some "Jack Tips" on the use, care and treatment of SI carbs.
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Addicted
2005 Stellalossi 177 Fe
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Location: MA
 
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UTC quote
To say that loses something in the translation would be an understatement.

The discussion of throttle slides was reasonably clear though. Bottom line: he says if you have a big bore kit, you want a No. 7 slide (flat bottom) or a No. 1 slide (smallest cut-out on bottom).

Wish I could make sense out of his discussion of air tubes and mixer tubes.
@ray8 avatar
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Molto Verboso
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Molto Verboso
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UTC quote
Kowalski wrote:
To say that loses something in the translation would be an understatement.

The discussion of throttle slides was reasonably clear though. Bottom line: he says if you have a big bore kit, you want a No. 7 slide (flat bottom) or a No. 1 slide (smallest cut-out on bottom).

Wish I could make sense out of his discussion of air tubes and mixer tubes.
Oh yeah, the slide ( the "guillotine"). Another ball to juggle.
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UTC

Ossessionato
2007 Stella 225
Joined: UTC
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Location: Rochester, Minnesota
 
Ossessionato
@christopher_55934 avatar
2007 Stella 225
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Location: Rochester, Minnesota
UTC quote
Kowalski wrote:
To say that loses something in the translation would be an understatement.

The discussion of throttle slides was reasonably clear though. Bottom line: he says if you have a big bore kit, you want a No. 7 slide (flat bottom) or a No. 1 slide (smallest cut-out on bottom).

Wish I could make sense out of his discussion of air tubes and mixer tubes.
I made sure Stella had a flat slide and blocked the oblong hole in the top next to the throat. I wanted to try and make sure as much of the air coming in had fuel and oil mixed with it.
@ray8 avatar
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Molto Verboso
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Molto Verboso
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UTC quote
Christopher_55934 wrote:
Kowalski wrote:
To say that loses something in the translation would be an understatement.

The discussion of throttle slides was reasonably clear though. Bottom line: he says if you have a big bore kit, you want a No. 7 slide (flat bottom) or a No. 1 slide (smallest cut-out on bottom).

Wish I could make sense out of his discussion of air tubes and mixer tubes.
I made sure Stella had a flat slide and blocked the oblong hole in the top next to the throat. I wanted to try and make sure as much of the air coming in had fuel and oil mixed with it.
It'd nice if there were a dictionary of the YouTube Italian translations.
I got Guillotine and Wasp, so far.
Each of these slides, atomizers, jets, etc were made for a particular bike's design, right?
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UTC quote
I think the next time I build a tuned largeframe engine, I'm going to use a Mikuini BN carb from a jetski.

Seems perfect as it's downdraft, and has a built in pump.
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Nedminder
62 VBB1T Round Tail W/ leaner sidecar
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Location: california
 
Nedminder
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UTC quote
Quote:
I think the next time I build a tuned largeframe engine, I'm going to use a Mikuini BN carb from a jetski.

Seems perfect as it's downdraft, and has a built in pump.
That's a pretty slick idea.
I see they are called 40-43?
Is that MM??
That'd be a whole lotta carb.
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2005 Stellalossi 177 Fe
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UTC quote
Ray8 wrote:
It'd nice if there were a dictionary of the YouTube Italian translations.
I got Guillotine and Wasp, so far.
The translations range from comical to confusing. His term for the cut-out on the bottom of a throttle slide is "scasso," which YouTube translates as "burglary." His term for the air correction tube is "freno aria," which YouTube translates as "air brake."
@christopher_55934 avatar
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2007 Stella 225
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UTC quote
charlieman22 wrote:
Quote:
I think the next time I build a tuned largeframe engine, I'm going to use a Mikuini BN carb from a jetski.

Seems perfect as it's downdraft, and has a built in pump.
That's a pretty slick idea.
I see they are called 40-43?
Is that MM??
That'd be a whole lotta carb.
A 34mm version
https://thejetskistore.com/index.php/mikuni-jet-ski-34mm-carb-13-5057.html
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UTC quote
the 34-28 seems to be the smallest, and would be just about perfect. the Venturi is 28, so throttle response should still be good.

Only time i've seen one used on a vespa was in the '80s with an RZ350 cylinder. that bike moved!
@ray8 avatar
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Molto Verboso
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Location: Los Angeles
 
Molto Verboso
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UTC quote
Kowalski wrote:
Ray8 wrote:
It'd nice if there were a dictionary of the YouTube Italian translations.
I got Guillotine and Wasp, so far.
The translations range from comical to confusing. His term for the cut-out on the bottom of a throttle slide is "scasso," which YouTube translates as "burglary." His term for the air correction tube is "freno aria," which YouTube translates as "air brake."
Yeah, hilarious! A brief dictionary would help a lot, even if just for laughs.
Vespe e Motore's excellent YouTube videos (also in Italian) are much more physically descriptive, which helps a lot. Unfortunately, he hasn't yet made an SI tuning video.
@ray8 avatar
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Molto Verboso
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Molto Verboso
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UTC quote
Christopher_55934 wrote:
Kowalski wrote:
To say that loses something in the translation would be an understatement.

The discussion of throttle slides was reasonably clear though. Bottom line: he says if you have a big bore kit, you want a No. 7 slide (flat bottom) or a No. 1 slide (smallest cut-out on bottom).

Wish I could make sense out of his discussion of air tubes and mixer tubes.
I made sure Stella had a flat slide and blocked the oblong hole in the top next to the throat. I wanted to try and make sure as much of the air coming in had fuel and oil mixed with it.
How'd that go? I tried this a while back (blocked the oval hole on the filter, in order to essentially negate the slide's cut-out effect).
Didn't help at all. But at that time I didn't realize I was already rich in the middle third of the throttle range.
@christopher_55934 avatar
UTC

Ossessionato
2007 Stella 225
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Posts: 3547
Location: Rochester, Minnesota
 
Ossessionato
@christopher_55934 avatar
2007 Stella 225
Joined: UTC
Posts: 3547
Location: Rochester, Minnesota
UTC quote
Ray8 wrote:
Christopher_55934 wrote:
Kowalski wrote:
To say that loses something in the translation would be an understatement.

The discussion of throttle slides was reasonably clear though. Bottom line: he says if you have a big bore kit, you want a No. 7 slide (flat bottom) or a No. 1 slide (smallest cut-out on bottom).

Wish I could make sense out of his discussion of air tubes and mixer tubes.
I made sure Stella had a flat slide and blocked the oblong hole in the top next to the throat. I wanted to try and make sure as much of the air coming in had fuel and oil mixed with it.
How'd that go? I tried this a while back (blocked the oval hole on the filter, in order to essentially negate the slide's cut-out effect).
Didn't help at all. But at that time I didn't realize I was already rich in the middle third of the throttle range.
I can't say, I don't have anything to compare to, I did that about the same time I completely removed the air filter and put on one of Patrick's venturi's.
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2005 Stellalossi 177 Fe
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UTC quote
For whatever it's worth, I checked my throttle slide today. This is for a 2005 Stella with Spaco/SI 20-20 carb. Given that Stellas were tuned to meet US emissions requirements, I was expecting a slide with some kind of cut-out. I was very surprised to see the carb already had a No. 7 flat bottom slide. Since I am only the second owner, and since I know enough about the first owner to know there is no way he would have been futzing around with throttle slides, I have to infer this was original equipment.
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