Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

Yeah I suppose this cam/shaft type deal to control both carbs with one cable works when they are right next to each other but for carbs in totally different locations won't really help.

Re: Are dual carb Vespas REAL?

The cam might be a good option . It could be located almost anywhere with cables to each carb .

Might take a little imagination , but , doable .

Re: Are dual carb Vespas REAL?

Dirty30 Dillon /

> Jason ( ͡° ͜ʖ ͡°) Wrote:

> -------------------------------------------------------

> Yeah I suppose this cam/shaft type deal to control both carbs with one

> cable works when they are right next to each other but for carbs in

> totally different locations won't really help.

Doesn't really matter, the cam is just a ratio changer that has one cable in and two cable outputs to mount things wherever you want. Even with dual carb vespas, it's no farther apart than typical carb and oil pump setups that feature the cam.

Re: Are dual carb Vespas REAL?

so alright...lets think logically here...what does more carb size do to HP curve?

Once you answer that question, I think you'll come to the same conclusion I have where one is controlled with a regular throttle and the other is controlled with a thumb throttle.

Re: Are dual carb Vespas REAL?

> LSLB RXb Wrote:

> -------------------------------------------------------

> so alright...lets think logically here...what does more carb size do to

> HP curve?

^^progress reports?

Weird thing about jetting is the bigger the carb the bigger the jet needed. This always confused me, change nuthing elese except bigger and the jet has to go up 15 sizes... well as simple as it may sound the bigger the hole the less speed the aur is moving, hence you need a bigger jet just to able to suck gas up. So producing perfect a/f ratio across the rpm board is the goal, carb designs attempt that under different coditions.

. We all wanna dump fuel right before the pipe hits. So obvious answer is just open up the other carb with a thumb throttle as you need more performance...but as you open thumb carb up its decreasing airflow speed across both carbs hence less gas flow.

I think attaching both carbs to one throttle cable and thinking of them as one multicircuit carb would make tuning easier. Say if ya wanted to dump a richer mix toward the top rpm end using the tiny sha. Id probably have it open later and to get it going right off the bat keep a flat slide and possibly drill out the idle passage, two carbs, too many freekin variables.

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

Yeah I think there is a TON of potential variation as far as A/F tuning goes and that's the wild card to me about this build it could either be huge for fine tuning the setup or just be a complete PITA. We will just see I guess.

I've had to put thinking about carb tuning on hold while working on other parts of this build. A friend helped me turn some holes in stock cranks for the pinasco case half (11mm hole with 1mm milled off the face, per pinasco's instructions). I also started modifying my stock case inlet as well as just test fitting everything together.

The QC on the pinasco half was terrible. The hole for the stud was misaligned by ~1.2mm so I had to use a round file to open up that hole in the cylinder. And the round channel for the cylinder skirt was rubbing hard too because of that, so I also sanded that down a little so I wasn't opening up the hole in the cylinder too much. Everything is fitting together nicely now though and I'm onto some case matching, degree measuring, port grinding, and crank cutting to play nicely with the 43mm Malossi kit. Taking lots of photos for a build thread as well which I decided I'll just save for later.

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Re: Are dual carb Vespas REAL?

Where does the hole in the crank go? Can you enlighten me please?

Re: Are dual carb Vespas REAL?

> EH FCC of the QCB Wrote:

> -------------------------------------------------------

> Where does the hole in the crank go? Can you enlighten me please?

Maybe directly in line with the hole in the carb mount ?

And , the other end of the hole just dumps between the counter weights of the crankshaft . ;)

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

The hole goes exactly in the center of the small side of the crank. The nub that the bearing goes on. You machine an 11mm hole and also take 1mm off the face. Then be sure to round it up a little. I'll post a photo of the pinasco instructions at some point.

Yeah honestly the intake pulse hitting a steel wall on the inside of the crank probably isn't the best for flow and eddying but hey, I guess it's something you can't really change with the pinasco case half. There really isn't any amount of modification that would improve that ... That I can think of.

Re: Are dual carb Vespas REAL?

Ya post some pics I am curious

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

> EH FCC of the QCB Wrote:

> -------------------------------------------------------

> Ya post some pics I am curious

Here are the instructions that came with my pinasco small case half kit (the 43mm version).

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Re: Are dual carb Vespas REAL?

todd amundson /

You still using the intake pad for duration right? It’s a small area I get it but doesn’t the walls around the window increase the charge sealing area? This the closest one I’ve seen?Dude the charge has plenty of area going through one web and dissipating before hitting the wall 10mm away. My big reed ciao has a charge hitting a solid full circle web head on. Not ideal but still shreds.

Re: Are dual carb Vespas REAL?

> Jason ( ͡° ͜ʖ ͡°) Wrote:

> -------------------------------------------------------

> > Yeah honestly the intake pulse hitting a steel wall on the inside of the

> crank probably isn't the best for flow and eddying but hey, I guess it's

> something you can't really change with the pinasco case half. There

> really isn't any amount of modification that would improve that ... That

> I can think of.

Is the inside of the opposing counter weight flat or slightly dished ?

My Simplex has a through crankshaft intake . That intake dumps against a slightly concave stuffer plate .

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

> todd amundson Wrote:

> -------------------------------------------------------

> You still using the intake pad for duration right? It’s a small area I

> get it but doesn’t the walls around the window increase the charge

> sealing area? This the closest one I’ve seen?Dude the charge has plenty

> of area going through one web and dissipating before hitting the wall

> 10mm away. My big reed ciao has a charge hitting a solid full circle web

> head on. Not ideal but still shreds.

Oh hell yeah I know it's gonna rip! But it's still less than ideal for it to shoot into the other half of the crank web but it's like the only way to do it I guess.

Yes, rotary intake is for my 1st carb. I've done intake patches this wide on multiple vespas and they RIP, no issues sealing. Generally I was told by others as long as you leave 1-2mm of material around the edge you will be fine with sealing. The width of the sealing edges is only half of the battle though as the web of the crank needs to sit between .25mm and .35mm away from the sealing surface. And with the variation is production of both stock and aftermarket cranks that often isn't the case.

I'm not done with that intake patch modification though. As it sits now the right and left, opening and closing, edges are too rounded and oval shaped. I need to make them more square so that the patch opens and closes much more abruptly and the intake pulse is a lot stronger. (edited)

Re: Are dual carb Vespas REAL?

Ľ̷̝̽͒i̶̛̼͑͠ȁ̸̧̛̽m̵̻̟̯̀̅ ̷͎̙̽̊F̶̲̺͑̓ F /

Any plans for tri carbs?

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

Haha well once I get your biturbo kit it'll totally not be unobtainable if I can fab a different intake or modify the existing one. Or maybe there's one off the shelf that will work. The stock one will interfere with the carb on the pinasco half.

My plan was to try dual carb with rotary and biturbo piston port, then pinasco reed and burturbo piston port, before even attempting triple ever haha.

Re: Are dual carb Vespas REAL?

Ľ̷̝̽͒i̶̛̼͑͠ȁ̸̧̛̽m̵̻̟̯̀̅ ̷͎̙̽̊F̶̲̺͑̓ F /

I believe most puch reed intakes will fit, you may be able to fit a carb in front of the engine on some of the subframe models

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

Just came across something pretty cool on ciao nl. It looks like there exists/existed another small case half kit with induction through a hole in the crank, they call it the "TURBO / “ATG side inlet". This specific setup appears to have come with a special crank that not only utilizes a larger bearing for a much larger hole in the crank shaft on the small side . . . but implements these series of "slits" in the side of the crank to, as they put it, "mix the gasoline with the air well and thus get better combustion".

This is super interesting, photos attached. I guess these slits maybe help to grab and "swing", in a way, fuel around the crankcase to better homogenize the air/fuel mixture?

I wonder how much more effective this is, and if it's only significantly more effective when you have such a larger side intake pumping more fuel. This one looks like it's maybe even 19mm, it's huge. Would a rotary intake only setup benefit from something like this? Pretty cool, I have never seen these before that's for sure. It's pretty badass how this half uses such a larger bearing and cup in the small half to allow for such a bigger hole in the shaft. I guess it's only possible when you are requiring a specific unique crank.

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Re: Are dual carb Vespas REAL?

Dirty30 Dillon /

Ahhhh yeah, the eurocilindro kits. Some dudes swear by these, buy they're just so hard to get. Very interesting design with the slinger built into the inner cheek.

Re: Are dual carb Vespas REAL?

Man that's weird!

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

Was browsing around on BDK Race Engineering's website for some Kawasaki AR stuff for one of my other bikes, and stumbled across these 2/3/4 pull throttles. These are apparently intended for large cc multi cylinder 2 stroke racing beasts, like the Suzuki TR750 or RGB500, but would probably work great for a dual or triple carb moped.

Unfortunately these specific ones are wildly expensive haha but maybe there are cheaper multi pull throttles out there. This may be a good route instead of splitting a cable.

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Re: Are dual carb Vespas REAL?

This is for those multicylinder French peds from Turkey.

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Re: Are dual carb Vespas REAL?

Ľ̷̝̽͒i̶̛̼͑͠ȁ̸̧̛̽m̵̻̟̯̀̅ ̷͎̙̽̊F̶̲̺͑̓ F /

Another solution I was thinking about that would retain the stock cable end is 2 levers, one for the input and one for the output mounted to transmit the force

Re: Are dual carb Vespas REAL?

Frederick vdL /

On my triple carb Ciao I run the side and rear 13.13 carbs simultaneously, and the top reed valve carb (that sits on top of the cylinder) separately on a lever (on the left side of my "steering wheel").

- Also, our MOPARTS RACING Subframes are back in stock as of end of January. Can be ordered now already - CLICK HERE

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