ESE's works engine tuner

[husaberg]

I think you are going to get lost - running a 4T bleed type emulsion tube and trying to tune that, assuming its a primary correction system is asking for trouble.
My take is that ALL modern 2Ts have primary emulsion correction only, wherein all the correction air bleed is fed into the well around the shroud.
It must be obvious that its well proven that is all that is needed to get a perfect fuel curve.
Having a 4T type air bleed emulsion tube, with a series of holes is just a confusing tangent you simply dont need - and very few understand.
Weber and Dellorto have hundreds of variations, you have one tube - and you have no idea what it is doing, nor where or why , in the powerband.
Your call, but seems you'r asking for brain damage to me.

The Japs are sticklers for corporate integrity - yes Mikuni have variable tube diameters,and only change the needle angles, and taper start point.
Keihin on the other hand have a single tube diameter - usually a machined hole in the casting, and vary the parallel diameter of the needle range, plus the taper start point.
No advantage to either - apart from being not being the same - not allowed,in the Land of the Radioactive Sun.

I am a bit torn myself the oko's seem to be a leap ahead of the old PJ Keihins. as bucket mentioned above most of the Keihin tuning was on the taper only as the needle jet system was an integral part of the carb and not available as a separate part hense the frustration of tuning a worn Keihins where fatter needles with differing taper's were required to compensate for worn carbs.
But Tz seems to have it close and adjusting the air correction jet is quick and easy esp if it is tapped for a jet and would seem from the symptoms Rob describe to be worth a go because it will affect the area of carburation that rob says is out.
Oh fiddling with the Air correction is something practically every one who had a decent running Rotary Mazda had to do to their IDA Webbers.

But yeah emulsion tubes do my head in. I can never understand why with the Disk valve engines on Mikunis have 4 stroke style Primary bleeds with short shrouds. i know that the shroud is for, but why different between Disk and piston port or reed?

PS doesn't the evil empire own Keihin as well as Showa

I must have a look at a Keihin air striker. As they seem to have a different set up with more vents possibly a high speed air correction?

[ief]

This is getting confusing.

As on the net usually people say; primary = 4 stroke and bleed = 2 stroke.

Wob says other way around?

[wobbly]

Where I come from the" bleed " type allows air into the emulsion tube body via a series of holes.
The size and position of the holes bends the fuel curve in very specific areas of the rpm band - a nightmare to get right,but VERY effective in operation.

The so called "primary choke " type has a shroud above a well in the tube,that extends into the air stream.
This shroud creates a situation very similar to having an auxiliary venturi - or choke , as seen on pumpers, and performance units like Webers and V8 carbs.
The height of the shroud, and an air bleed into the external well below it,changes the fuel curve shape externally from the emulsion tube.

Mikuni have used bleed type carbs on various applications ( Yamaha twins ) - but it wasnt long before they changed to the primary type for all 2Ts.
Dellortos as run on Rotax/Aprilia disk valves are all primary type.

The air strikers are just normal Keihins, with an air guide in the bottom of the venturi below the slide.
This is supposed to increase the velocity past the shroud at low throttle openings, giving better response.
Maybe it does - but they loose power everywhere else,due to turbulence I assume.
In a 50 Hp 125 a 38mm air striker looses 2 Hp right thru the powerband to a PWK - same jets,same length etc.

[husaberg]

This is getting confusing.

As on the net usually people say; primary = 4 stroke and bleed = 2 stroke.

Wob says other way around?

Most But Not all,Mikuni equipped 2 strokes have a P type Needle jet that have a single air bleed hole

Most but not all Mikuni equipped 4 strokes have a (B type)That have a series of holes.

There are some exceptions with regards to some disk valve bikes and some other road bikes.

According to Bell a least.
The P type (Mainly used on two strokes)the air that comes from the air bleed orifice is mixed with fuel which has already been metered by by the needle and jet.

The B Bleed type (mainly used of four strokes) however is designed to hold air and in the body section of the needle jet so in this case Fuel and Air (a frothy mix) is metered by the needle and jet.

As Wob says above the height of the should can alter the fueling curve a fair bit similar should extensions are used in almost all Dynojet kit for the Diesel's to create a greater depression.
the pic Rob posted a page back shows as a example of a curve of how it can alter the fueling.
(As this is from Robinson i guess Leon Moss came up with the data?)

Looking for a high speed air bleed came accros this I suspected scooters may be good some something maybe once i guess it was stolen of a bike forum or Gorr i guess.
http://www.shiny-red.net/tuning-guid...uretor-jetting

Of course it always must be remembered carb tuning is all about compromise of overlapping circuits that interact.
not a complete graph but......
Then start throwning in altitude, temp, humidity, rider style, engine spec.....................


Last attachment is a PDF of the Mikuni tuning guide for the VM carb

[cotswold]

Sad piston

[kel]

Sad piston

Very sad. Mate that looks like a lube problem, you werent using that expensive oil that seperates from the fuel were you?

[cotswold]

Very sad. Mate that looks like a lube problem, you werent using that expensive oil that seperates from the fuel were you?

Motul 800 at 20:1 ....... Castrol R never did that and smelt nice too

[TZ350]

http://en.wikipedia.org/wiki/Exhaust...ssure_charging

Exhaust pulse pressure charging (EPPC) is a system for supercharging two-stroke of the loop-scavenge type. The exhaust system is arranged in such a way that excess air/fuel charge follows the exhaust gases into the exhaust manifold. Some of this air/fuel is then forced back into the cylinder by a rise in pressure in the exhaust manifold.

http://en.wikipedia.org/wiki/Pressure_wave_supercharger

A pressure wave supercharger The process is controlled by a cylindrical cell rotor whose speed is synchronised with the engine crankshaft speed via a belt or chain. Individual cells alternately open and close the exhaust gas and fresh air apertures, when the aperture on the exhaust gas side is reached pressurised exhaust gas flows into the cell and compresses the fresh air there.



As the cell rotor continues to rotate and reaches the aperture on the inlet side the compressed air flows to the engine. Before the exhaust gas can flow the aperture is closed again and the exhaust gas column is reflected before entering the engine. The exhaust gas exits at high speed sucking further intake air into the cell behind it repeating the process.

Energy exchange in the pressure-wave supercharger occurs at sound velocity, resulting in good response even at low engine speeds, a common downfall of turbocharged engines. It combines the advantages of mechanical and exhaust gas supercharging.



http://www.idsc.ethz.ch/Research_Guz...e_Wave_Systems


A ton of information on wave rotors can be found here:- http://www.egr.msu.edu/mueller/projects_waverotor.htm


So if a 2-stroke is already supercharged by the exhaust system, then would it be ok to extend the inertial pressure wave process to the inlet side?

[husaberg]

Steady Eddie Lawson the solid reliable performer.
Er i guess even he was led astray by Kenny Roberts.

Kid in the story Jake Zemke http://en.wikipedia.org/wiki/Jake_Zemke

Seizure above, A747 or Castrol R will fix that, boring aye

[TZ350]

Rich and Bert have talked about them before and Thomas is having a go at building one of these head phone det sensors, all the bits can be brought from JayCar.

Construction details here:- http://autospeed.com/cms/A_1353/article.html http://autospeed.com/cms/article.html?&A=0348

[speedpro]

Motul 800 at 20:1 ....... Castrol R never did that and smelt nice too

You can't possibly be blaming lubrication for that, surely?

When I ran Motul 800 it was at 40:1 and I "never" had a problem.

[husaberg]

You can't possibly be blaming lubrication for that, surely?

When I ran Motul 800 it was at 40:1 and I "never" had in problem.

"When i ran" Is a series of words that suggests "Previous tense"
What were you running in this pic?

[cotswold]

Seizure above, A747 or Castrol R will fix that, boring aye[/QUOTE]

Erm I was taking the pro·ver·bi·al stopped using R when I sold the MTR back in 1984

[husaberg]

Seizure above, A747 or Castrol R will fix that, boring aye

Erm I was taking the pro·ver·bi·al stopped using R when I sold the MTR back in 1984[/QUOTE]

Er siezeures are boring was it to subtle
btw if you can show me a oil that actually works better "as a lubricant" than a Castor based oil i would be keen to see it.
Maxima 927 has supposedly the same smell.(mmmmm....Sweet) is less dirty and gummy yet still retains the unique castor properties.

[cotswold]

was it to subtle

I'm more of a hit with a brick type, subtlety tends to go unnoticed.