Hp-carb selection graph
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Re: Hp-carb selection graph
All the more reason I should switch to a 24mm instead of this d*** 28mm!
84 Honda Spree... The plastic at least.
- Rip_City_Spree
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Re: Hp-carb selection graph
My 24 on my Corsa is plenty
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polini corsa
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polini corsa
Polini 26mm Carb
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Currently 5g rollers
zx trans
Arrow
red contra with yellow clutch springs.
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Re: Hp-carb selection graph
tuning carb is trail and error..
28mm carb work good on hawaii climate..
the polini cp 21mm, inlet was measure 28.5mm
28mm carb work good on hawaii climate..
the polini cp 21mm, inlet was measure 28.5mm
Re: Hp-carb selection graph
Just Joel wrote:All the more reason I should switch to a 24mm instead of this d*** 28mm!
lol
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Re: Hp-carb selection graph
It doesnt. They're probably are compensating for air leaks. Those charts are made by engineers with thousands of hours of r&d yet some people on the island just think they know better. Just like they claim theyre running mhr cylinders over 450 constantly. Yeah right. For shame, for shame.graphite9 wrote:You don't measure the inlet at the filter end..Its the center.veedubh20 wrote:tuning carb is trail and error..
28mm carb work good on hawaii climate..
the polini cp 21mm, inlet was measure 28.5mm
A 28 was too large for my 72 MXS mina vert, which makes an advertised 19hp. Can anyone explain why the larger carb would work better in hawaii?
The rest of the great tuners and engine builders who are truthful know 28mm isn't for a these tiny engines.
**edited for "the love of being pc" which I lack.
Last edited by 1man8scoots on Sun Nov 08, 2015 10:53 am, edited 1 time in total.
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Re: Hp-carb selection graph
It's the same mentality that the cps inlet size matters are the same few challenged individuals that think a 28mm is perfect for a 72cc.. The venturi is the ONLY factor. I run 26mm carbs on stroked and bored 244 cc 20++ hp blaster engines and 28mm carbs on stroked and bored 68 whp 421cc banshees. And on my stroked and bored 29 hp kx65/82 I run a 24mm.
I have real people who have rode my bikes on this forum who can verify my engines run amazing with these carbs. So amazing they're scary.
In order to run a 28mm carb on the mxs kit to hit 19 hp they have a full race set up and that cylinder isn't truly for the street so it is designed to run with in the race world parameters. Such as never dipping below 9k rpms.
The truth is out there you just have to be willing to listen to those who have put the real time into the r&d. Further more... if these people know better than these professional engineers and developers, why are they not in job positions that suit their "skills".
I have real people who have rode my bikes on this forum who can verify my engines run amazing with these carbs. So amazing they're scary.
In order to run a 28mm carb on the mxs kit to hit 19 hp they have a full race set up and that cylinder isn't truly for the street so it is designed to run with in the race world parameters. Such as never dipping below 9k rpms.
The truth is out there you just have to be willing to listen to those who have put the real time into the r&d. Further more... if these people know better than these professional engineers and developers, why are they not in job positions that suit their "skills".
- Wheelman-111
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Re: Hp-carb selection graph
Greetings:
The carb size is determined by the diameter of its venturi, the narrowest part of the Hourglass shape that creates the negative pressure to draw fuel. You can measure the slide bore or the slide itself, but not the bellmouth or the spigot. OKO carbs for example ALL have the same 50mm bellmouth diameter.
Tuning can compensate, partially, for an oversized carb, but it's challenging to get it running right at low, middle, and high RPM. The carb only starts to work properly when the revs head for the moon.
For the record, I gained about 2 MPH, to 71.2 from 69, when I switched from a 24mm to a 26mm OKO. Low end was acceptable, but fuel consunption was pretty high and the Corsa needed over 10, 400 RPM for optimum thrust. Not much fun on streets with frequent stops. I believe with more tuning I could eventually have gone as fast with the 24, maybe even a 21, but the bigger OKO was sort of a shortcut to bragging rights.
The carb size is determined by the diameter of its venturi, the narrowest part of the Hourglass shape that creates the negative pressure to draw fuel. You can measure the slide bore or the slide itself, but not the bellmouth or the spigot. OKO carbs for example ALL have the same 50mm bellmouth diameter.
Tuning can compensate, partially, for an oversized carb, but it's challenging to get it running right at low, middle, and high RPM. The carb only starts to work properly when the revs head for the moon.
For the record, I gained about 2 MPH, to 71.2 from 69, when I switched from a 24mm to a 26mm OKO. Low end was acceptable, but fuel consunption was pretty high and the Corsa needed over 10, 400 RPM for optimum thrust. Not much fun on streets with frequent stops. I believe with more tuning I could eventually have gone as fast with the 24, maybe even a 21, but the bigger OKO was sort of a shortcut to bragging rights.
Wheelman-111
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Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
Re: Hp-carb selection graph
I just jetted in a 28mm oko on a corsa 72cc bore... 154/55 in order to deal with the low vacuum/air velocity due to the large (too large) venturi. These jets are massive and are obvious compromise/compensation. Like stated, it provides adequate pull through all stations but literally drinks fuel. My little spree tank doesn't last long lol. Will be moving to a Polini 24mm setup. Best way of looking at it is if you actually down jet with a smaller venturi, your over carbed.
84 Honda Spree... The plastic at least.
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Re: Hp-carb selection graph
Hmmm. Anyone have an idea of what polini and malossi af05 bores are at for HP? Can't imagine it's much above 8.