ESE's works engine tuner

[bucketracer]

Oh i do love an historical debate .....

Turns out TZ is in the hunt for HP with the works bikes though admittedly piston ported and liquid cooled twin cylinder ones from 1970's.

TeeZee Suzuki GP125 commuter bike engine is from the 70's too .......

[wobbly]

I think its a good time to remind everyone that the whole reason we heard about the possibility that 30 Hp was feasible from a 100 bucket was due to the software I was
using at the time.
Now, we plug TeeZees 125 Aircooled engine into the latest version of EngMod and voila we get a result.
Gaining the experience to run the software effectively is time consuming - but nothing like the time it would take to learn the hard way, what not to do.

[husaberg]

I think its a good time to remind everyone that the whole reason we heard about the possibility that 30 Hp was feasible from a 100 bucket was due to the software I was
using at the time.
Now, we plug TeeZees 125 Aircooled engine into the latest version of EngMod and voila we get a result.
Gaining the experience to run the software effectively is time consuming - but nothing like the time it would take to learn the hard way, what not to do.

Your post got me thinking about a thought i had the other day, Which is something (2 thought per week) i generally avoid for obvious reasons.

The sim's are fantastically awesome tools. Indeed Great predictive models of what can happen if you do this or that etc.
The writer's of the programs are fiendishly clever people and so are the people who can get them to work accurately but i can see one major limitation.
They only will express known parameters. Like a Map really or a recipe

Is the 2 stroke a the stage when there is nothing new to discover with the two stroke. I don't think so .....yet.
But how will the new discoveries be made if all the clever people are using them to test theories.
I do understand that Neel's is updating the sim regularly. But is there new ingredients available or missing to create a new spicy dish

I for one will be using Wobs experience with the Sim to design the engine and his real world experience that he has also attained. for my part...but
How will we know if we are missing something with 2 stroke development?

Also does it mater that most of the people under 20 think 4 strokes are faster than 2 two strokes. and yet they have never ridden a modern two stroke.

[Bert]

.....
The sim's are fantastically awesome tools. Indeed Great predictive models of what can happen if you do this or that etc.
The writer's of the programs are fiendishly clever people and so are the people who can get them to work accurately but i can see one major limitation.
They only will express known parameters. Like a Map really.

Is the 2 stroke a the stage when there is nothing new to discover with the two stroke. I don't think so .....yet.
But how will the new discoveries be made if all the clever people are using them to test theories.
I do understand that Neel's is updating the sim regularly.

I for one will be using Wobs experience with the Sim to design the engine and his real world experience that he has also attained. for my part...but
How will we know if we are missing something with 2 stroke development?

valid points Husaberg; like all sims/models the quality and understanding of the back end calculations & required parameters are critical to the success of the generated information. It great the Wobby can apply his real world knowledge in enhancing his sims and Neels also continuing improvement to his product. must get me a copy (it must be more interesting than spending time fixing fluvial Hydraulic models...)

I'm guessing as long as people continue to play with Two strokes and can relate there "new" developments to calculable parameters then there will be endless improvement to Sims. I Think we are only at the start of two stroke development...

.....
Also does it mater that most of the people under 20 think 4 strokes are faster than 2 two strokes.

Hummm well that's what they are brought up on... and I blame MX (well Honda really). gee I'd hate to be a MX dad these days... $$$$$$... whats wrong with a scruffy RM80??

What we really need here is for Mira motorcycles to produce a road going water-cooled 100cc "non race" 6 speed close ratio, two stroke...
Come on Wobby push them in the right direction
http://www.miramotorcycles.co.nz/motorcycles.html

[speedpro]

Good points.

Pete Sales told me a long time ago that he could build a 25rwhp Honda MB100. He actually did it and it had nice power, evidently. The knowledge to do that was all gained through trial and error over a lot of years. Anyone who knew him when him and Penny were still living in Blenheim will know how much time he put into tuning 2-strokes. He still holds the NZ land speed record for a 50 with his GT50 bucket. To get to 30rwhp by trial and error will take more time than one person who has to earn a living has in this world. His Suzuki TM400 was a sight to behold as well. It'd be real interesting to see what the simulation software could make of that.

The knowledge needs to be condensed and disseminated in a manner that is accessible to all. Which is where the simulation software comes in. Users of the software then need to spend time getting good with it, or pay someone who is.

[koba]

How will we know if we are missing something with 2 stroke development?

When you have the fastest bike you think is possible and some other sod comes and blows your wheels off.

[koba]

Is the 2 stroke a the stage when there is nothing new to discover with the two stroke. I don't think so .....yet.
But how will the new discoveries be made if all the clever people are using them to test theories.
I do understand that Neel's is updating the sim regularly. But is there new ingredients available or missing to create a new spicy dish

I'm just spit-balling here, not really agreeing or disagreeing, just adding some more thoughts to the mix.

I think those at the cutting edge of the technology need, and do have, a very clear and thorough insight into what's going on inside the engine.
If they didn't that wouldn't be pushing boundaries and making gains.

Those who progress past the known limits will do so regardless of whether or not they use a sim to get to that point.
They get there by identifying the limiting factors and finding a way past them (as we have seen in this thread, but we are still really in in sim territory)
Those that just use the sim will still have a winning engine in all but the most fierce competition.

Physics is the only firm boundary, still we (collectively, man) manage to find new ways of making this better within these limits.

Abel Tasman would have had a map up to a certain point, it's how it goes and what is discovered after the map runs out is the tricky bit.
Cook did 'better' as technology and understanding of scurvy improved (and they took a sensible approach!)

Just as 'we' will do 'better' than those who were making fast bikes in the 60's.

(Except Frits, because he was probably making fast bikes in the 60's and is still contributing now!)

[TZ350]

With EngMod2T's help and a few valuable tips from Wobbly we have cracked 30+ but behind that is a lot of hardwork, considered study and dyno work.

[Frits Overmars]

I think those at the cutting edge of the technology need, and do have, a very clear and thorough insight into what's going on inside the engine.

I wish! I may know more than some, but not nearly as much as I'd like to know. And that's just about the things that I'm aware of.

If they didn't that wouldn't be pushing boundaries and making gains.

It is quite possible to blunder into new discoveries, unhindered by any knowledge. Although you have a better chance if you have some idea of what you are looking for.

Those who progress past the known limits will do so regardless of whether or not they use a sim to get to that point.

Just ask Jan Thiel what he thinks of sims: not much. I must add that I have a bit more confidence, but having written my own sims, I remain very aware of their limitations.

Abel Tasman would have had a map up to a certain point, it's how it goes and what is discovered after the map runs out is the tricky bit.

Everyone who tries to discover unknown territory, goes to the boundaries of what he knows. Beyond that, the guessing begins. Because no matter how much you studied, it will never be enough.

Just as 'we' will do 'better' than those who were making fast bikes in the 60's.(Except Frits, because he was probably making fast bikes in the 60's and is still contributing now!)

In hindsight, what I did back then, is a collection of blunders, with a hit every now and then. Looking back, I knew nothing then.
Looking back in ten years' time, I will probably say the same about now .

[TZ350]

Onwards and upwards towards the goal of a useable race bike. My interest at the moment is learning about air correction and how to use it to improve drivability in the lower part of the torque curve.

At the moment to get best power at the top I have to use a 110 mj but best drive in the lower part of the torqe curve is with a 118-120mj. My plan is to fit the mj main jet that works best at the lower end and then adjust the air correction jet and emulsion tube untill I get the top end back, anyway thats the plan but first I need to find out all I can about air blead jets and emulsion tubes and how they work.

You would have to be an idiot, not to use Google for researching this sort of stuff, there is so much info out there. Below is Weber and VW stuff and with a bit of intelligence its possible to relate it to tuning motorcycle carbs.

http://www.aircooled.net/gnrlsite/re...es/jetting.htm

Carburetors are simply devices that meter fuel depending on the amount of air that is entering the engine. There are a couple problems though! Air and fuel have different viscosities, and since air and fuel do not flow the same, the metering of fuel is NOT LINEAR. What this means (if this didn't make sense to you) is that you can have a correct metering for a while, and then at certain RPMs it goes off. So, you have another set of jets to "correct" it and one more set to correct the correction!

Idle jets operate from idle to 2500-3000rpms or so. Main jets are primarily from 2500-4500rpms, and Air jets affect the engine from 3500/4000 on up. Lastly, you have emulsion tubes to change "where" it's rich, lean, etc. The complexity of jetting is that the operating range of the carburetor's jets OVERLAP, so a change in one area often MUST be accompanied by another change somewhere else,

Air Corrector Jet: The air jet jets AIR, not fuel! So, if you want to lean it out, you go BIGGER on the air jet, and smaller on the air jet if you want to richen it up! The air jet affects the engine from about 4000rpms up. You really have to wind it out to use this one, so be careful! Start with a baseline jet of 200. If it starts spitting and sputtering at high rpms, you need to richen it up, so change it to a 180 air jet. You are following the same procedure as the main jet, but your "operating window" is now 4000 RPMs up instead of the main jet's 2500-4500. I have seen air jets in the range of 160-240. If you are out of this range, you need to go back to the 200 air jet, and change emulsion tubes.

Emulsion Tubes: The Emulsion Tube mixes air from the air corrector jet with fuel from the main jet, and controls the mixture from the discharge nozzle at all engine speeds that the main jet is working! Basically, the Emulsion Tube changes the diameter and location of small holes in it's body. For Weber IDF carbs, the F7 or F11 is usually what you need. The F "series" has no rhyme nor reason to the numbering system, so you can't tell anything by the number unless you look it up! But, with these two examples, the F7 richens the mixture up at the bottom of the RPM range and under acceleration, while the F11 leans the mixture out on the top end a little bit, and is usually used (high RPMs) when you use air jets larger than 200.


Attachment 258382 Attachment 258385

http://www.rhinoracing.com/yaw/carb_tuning.htm

Air Bleeds
The air bleeds, or air correction jets, control the mixture mostly at mid to high rpm. The air bleeds are best described as a controlled air leak in the main circuit. The air bleeds work by "bleeding off" this vacuum which draws fuel through the main jets. A larger air bleed will make the mixture leaner at high rpm by bleeding off more vacuum or "signal." A smaller air bleed will richen the high rpm mixture by bleeding off less signal.

Emulsion Tubes
The air from the air bleeds enters the main circuit through the emulsion tube. The emulsion tube has a series of small holes from top to bottom, and it is through these holes that air enters the main circuit. At low engine speeds, when fuel demand is low, these holes are submerged in fuel, and so no air can flow through them. As engine speed increases, the fuel level in the float bowl drops, uncovering these holes, and allowing air from the bleeds to enter the main circuit, thus leaning the mixture. As the engine speed increases further, the fuel level in the float bowl continues to drop. This uncovers even more of the holes in the emulsion tube, which makes the air bleed have a greater effect on the mixture.

More from the net on Weber emulsion tubes:-

Emulsion tubes affect the shape of the fuel curve across a wide RPM range where a air corrector has effect at high speed.

Attachment 258389

Holes towards the bottom
low rpm enrichment or acceleration enrichment

Holes towards the top
low rpm leaning or acceleration leaning

More holes
high rpm leaning with air corrector larger then 2.0 mm

Smaller diameter tube low rpm acceleration with larger air corrector ( it does not say OD or ID smaller. I think increasing the liquid fuel in the emulsion well before the main circuit gets flowing causes this effect, so a smaller OD sounds likely ).

[wobbly]

Dont get all involved with the primary emulsion tube correction data from Webber etc - no 2T carbs use this system of air bleeding into the tube body.
All you have to tune with, is the main air corrector jet size dumping into the well at the top, more air = progressively leaner top end, along with the primary shield height around the needle.

[TZ350]

Dont get all involved with the primary emulsion tube correction data from Webber etc - no 2T carbs use this system of air bleeding into the tube body.
All you have to tune with, is the main air corrector jet size dumping into the well at the top, more air = progressively leaner top end, along with the primary shield height around the needle.

My Suzuki needle jets are like you discribe but the RD250/350 Yamaha and all the Kiehin ones I have, have a series of small air bleed holes like the Webers.

[husaberg]

Dont get all involved with the primary emulsion tube correction data from Webber etc - no 2T carbs use this system of air bleeding into the tube body.
All you have to tune with, is the main air corrector jet size dumping into the well at the top, more air = progressively leaner top end, along with the primary shield height around the needle.

The top section of the 2 stroke needle jet (the bit in the carb the needle passes through)
I have noticed that on Mikunis there is generally a large projection with the opening open towards the air entry of the carb with reed and piston ports. But with rotary valve and four strokes it is flat. Bell mentions it also but why is it the case.
Is it to do with intake velocity or is it to stop fuel enrichment from the signal passing back over the mainjet. I realise with Dynojet kits the glue in shroud i it increase the depression over the jets. I am sure generally most Keihins are not replaceable in the needle jet as well. Do the OKO's.

I have often thought this is the main difference between 2 and 4 stroke mikuni's and why it is problematic sometime to get mid range fueling right ion a Four stroke with a 2 stroke carb I always thought ah they need a four stroke needle jet with those holes in it.

[TZ350]

Air Bleeds
The air bleeds, or air correction jets, control the mixture mostly at mid to high rpm. The air bleeds are best described as a controlled air leak in the main circuit. The air bleeds work by "bleeding off" this vacuum which draws fuel through the main jets. A larger air bleed will make the mixture leaner at high rpm by bleeding off more vacuum or "signal." A smaller air bleed will richen the high rpm mixture by bleeding off less signal.

Emulsion tubes affect the shape of the fuel curve across a wide RPM range where a air corrector has effect at high speed.

Attachment 258389

Holes towards the bottom
low rpm enrichment or acceleration enrichment

Holes towards the top
low rpm leaning or acceleration leaning

More holes
high rpm leaning with air corrector larger then 2.0 mm

Smaller diameter tube low rpm acceleration with larger air corrector ( it does not say OD or ID smaller. I think increasing the liquid fuel in the emulsion well before the main circuit gets flowing causes this effect, so a smaller OD sounds likely ).

I can make more power (31rwhp) with a smaller mj but these two curves illustrate my point nicely. Insted of leaning it out on the mj and losing the bottom end of the torqe curve, I should look at changing the fuel curve to get the best at both ends.

Attachment 258395

Red line 150mj, Blue line 120mj, now what I wan't to do is use the air correction jet to lean the 150mj off towards the top end and the emulsion tube to tailor the curve so the two curves combine.

[wobbly]

From memory only a couple of RZ models used primary bleed tubes,then factory changed back to "normal" with a completely different setting.
All the Keihin 2T specific carbs like PJ ,PWK have no tube to remove, and only have air correctors.
The OKO must be used on 4T as well, but I do remember reading that 4T and rotary valve engines work best with the bleed hole setup.
Never seen one used though on any rotary valve 2T production engine.