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

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

Made a lot of headway on this build in the last few weeks. I was hung up for a while on how I should modify my crank, tranfers, and ports.

The pinasco 43mm small case half has a much different shape than the OEM small case half. There is actually a lot more meat on the outside of the OEM half, meaning you can open up the tranfers a lot better. The pinasco one not so much. I'm not a huge fan of using high heat epoxy or JB weld either.

Additionally I want the ability to swap kits on this bottom end until I settle on something. I have a polini and a biturbo kit to try on this bike after the malossi 43.

So, I ended up deciding not to touch the cases at all for now. Everything flows through the Swiss cheese piston on the malossi anyhow.

I did alter the intake timing, though, both by opening up the intake patch and cutting the crank. I made all my timing measurements after boring open the intake, but before cutting the crank. Here's what I got:

Intake Patch Opens @: 250 ATDC/110 BTDC

Intake Patch Closes @: 58 ATDC/302 BTDC

Intake Cycle Length: 168 degrees

Intake Patch Width: 39 degrees

Crank Web Width (stock): 125 degrees

Exhaust Duration: 162 (open/close @ 99)

Transfer Duration: 120 (open/close @ 120)

I wish I would have taken measurements before opening up the inlet. I would be curious if anyone has stock measurements? As you can see, though, opening the inlet alone makes for some pretty well improved intake timing numbers. I ended up wanting to aim for 185 degrees of intake timing vs the 168 that I had from doing just the inlet. And opted to

So I cut my crank ~8mm on the opening side and ~4.5mm on the closing side. This means the intake now opens at 130 degrees BTDC (which abides by Graham's suggestion of a 10 degree overlap between intake open and transfer close), and closes at 55 degrees ATDC.

Popped some bearings on and today this crank is going in the cases so I can start buttoning it up and getting the ignition installed.

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Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

Also rebuilt the transmission for this bike during the virtual CBBG event using the tall CIF gears. I have never run these taller gears only stock talk gears. I am hoping the bike will like the gears, previously I was really fast off the line and I'm hoping to trade some of that for top speed.

I'm also a dumbass and I busted a fork stanchion getting a seal out. So I have new ones on the way along with a mint super bravo gas tank in black that I'm stoked about. The plan is to weld a bracket for a front disc brake caliper onto one of these stanchions.

Had the rear wheel powder coated and just started test fitting everything, and that front wheel is actually a plastic polymer it's crazy light. I've never run a 17" rear wheel on a variated vespa either so that should be fun. The center brace on the Moparts subframe is in the forward most position and there is only about a 1/2" of clearance between the tire and the brace.

Still a lot to do, but should have a full roller that I can start tuning with shortly.

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Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

And in other news, Ryan Go dropped by from Milwaukee last weekend to grab a fairly complete Grande that I had lying around .... So y'all know what that means .... I lent it to him for R&D....

Vespa Cranks pipe in the works! I'm super super excited to see what he comes up with and ideally I'll have the dual carb engine running on this roller so we can test the pipe when he's done.

No more annoying ass proma circuits, and finally a decent vespa pipe! My hopes are high.

------------------------------------------------------------------

Also I don't think I mentioned this before but the stud hole on the pinasco case half was shifted off center by about 1.5mm from the stock location.

I couldn't get the jug to fit all the way down. So, I had to file out that hole on the jug. I just happened to have a perfectly shaped round file that made quick work of it. I tried to take a pic to show the misalignment but it didn't come out great so I won't even bother. But I took off a little bit of material and everything fits together snugly.

Lapped the head to the jug as well, on 400 then 600 grit sandpaper. Fresh rings, gap checked. Used piston but a nearly new cylinder. Once everything goes togeher this week I will make sure the piston clears all the ports, and then measure the compression to see where my starting point is.

I am going to try and run higher than stock compression and use a parmakit cdi box for the timing retard and I think that combined with the liquid cooled head should be able to keep the engine reasonably cool and free of detonation conditions even with the higher compression.

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Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

On an off topic note, is anyone planning to attend MopedGP East?

I'm hoping to ride this bike in the variated class.

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Re: Are dual carb Vespas REAL?

Dirty30 Dillon /

Are you just lapping with paper taped to plywood?

Re: Are dual carb Vespas REAL?

Jason ( ͡° ͜ʖ ͡°) /

For now to take off some material but it will hit a big piece of glass in my garage before I run it. I will do 600grit wet on the glass slab it's from an old table top it's real thick. I was primarily using the paper on the plywood for getting the carbon off the crown of my old piston.

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