ESE's works engine tuner

[twotempi]

Before anyone screams - please read the rest of this post.

A pre'72 classic two-stroke is probably stuck with a piston-ported setup. Even a pre'82 Yamaha TZ has this.

What is ( if any) the relationship between inlet timing ( symmetrical ) to exhaust duration/timing ??

For an exhaust duration of say 190 deg is the inlet duration a similiar value , or is any "overlap" between these two functions to be avoided ??

Any guidance would be greatly appreciated.

[cotswold]

Top Scooter 4 cylinder Engine, 2 stroke, 350cc that produces 110 HP ( thats what it said next to the photo )

Just spotted it and thought it was worth an airing

[2T Institute]

Thats pretty awesome. Are you drawing it on cad then using a cnc router on it ??

Flettner uses his favourite coping saw and a selection of wood chisels

[Haufen]

Before anyone screams - please read the rest of this post.

A pre'72 classic two-stroke is probably stuck with a piston-ported setup. Even a pre'82 Yamaha TZ has this.

What is ( if any) the relationship between inlet timing ( symmetrical ) to exhaust duration/timing ??

For an exhaust duration of say 190 deg is the inlet duration a similiar value , or is any "overlap" between these two functions to be avoided ??

Any guidance would be greatly appreciated.

When Yamaha ran piston ported engines in their GP bikes back in the days, the overlap did not seem to hinder peak horsepower. I forgot the figures, but I think it was in the ballpark of 200 / 200 exhaust and intake port. Of course, jetting becomes more difficult the longer the intake duration on a piston ported engine.

If anyone knows better and / or the exact figures please tell us.

[wobbly]

Here are the Inlet and Ex numbers of what is easily the fastest TZ350 ( 6 port 3G3 ) in the country.
Cylinder is dropped 0.4mm, the inlet ground up, and the Ex ground up further.
There are several hidden tricks in the inlet shape ( see 250G model ), and of course the Ex duct outlet is smaller than the effective port area,but thats secret so dont tell anyone.

[wax]

Top Scooter 4 cylinder Engine, 2 stroke, 350cc that produces 110 HP ( thats what it said next to the photo )

Just spotted it and thought it was worth an airing

There is a video of it running as well on you tube.
I have not seen one of it actually moving under its own power however.
It would be quite the beast I reckon

[RAW]

Judging from the way you wrote that word expand in italic, you have a pretty good idea yourself, Husa. A lower compression ratio before TDC equals a lower expansion ratio after TDC. That means a smaller temperature drop in the burnt gas during expansion, hence a higher exhaust gas temperature, a higher speed of sound in the gas and a higher resonance frequency in the pipe.

Frits, would you share some knowledge ?
The blank Aprilia little end pins, I have installed some, with no other changes.

Recorded weather data and tune up figures appear to no longer be valid, I feel it's now to rich for the same base line data

I surmise that a change to the Hermoltz / frequency side if things has rendered my tuning knowledge / history useless,

Anyone your experiences

[TZ350]

A pre'72 classic two-stroke is probably stuck with a piston-ported setup. Even a pre'82 Yamaha TZ has this.

Out of the box, a 1974 TZ350B's power delivery was like a light switch, all or nothing, after a few mods I got mine to drive very nicely without the abrupt pipeness they were known for.

My final port timing duration’s were:- Ex 200, Primary Transfer 126, Secondary Transfer 130, Inlet 180.

To get this I had to remove 0.75mm from the bottom of the cylinder. And adjusted the squish clearance to 0.025". The pistons just kissed the head, didn't hit but just polished the carbon away in the squish area.

Compression ratio was 15:1, running Av Gas with oil at 16:1 Castrol R, 15% Acetone. Ignition 1.8mm BTDC, Plug N82G gap 0.018". Ring gap 0.012" piston clearance 0.0025", Main Jet 350 left 340 right hand side.

If these things seized, they always seemed to seize on the left side so I ran that side richer and anyway tuning wise you had to treat a TZ as two seperate engines. Std 34mm Mikuni, float 24mm, main jet 320-360, needle 6F9 3rd, needle jet O-2, Slide cutaway 2.5 and pilot jet 70#.



This is a copy of a dwg of the TZ350B pipe I made back in the day. So I am not sure how accurate it is or if the dimensions are from the beginning of the actual pipe or from the piston face. From memory, max RPM for a TZ350B was 10,500 so quite a long pipe.

I see my notes for Pukekohe say, "started shaking with violent weave around the sweeper, had to put weight on the foot pegs each lap to keep control, found broken frame at the front left hand engine mount."

[husaberg]

EFI is not a waste of time and variable valve timing works for me. I'm starting to wonder after reading about so many EFI disasters on two strokes that I've just been lucky, muddling along with just enough knowledge to be dangerous. All I know is when EFI comes into play the design rules change. You can do a lot of things a carb will never do. I certainly won't be using a carb ever again. That Bighorn is running sweet now but it's not been easy.

I must admit i was a bit susceptible but when you think about it.
the Gp racing when at it's almost solely about winning, if the experiments Cagiva etc done didn't achieve almost results they were rejected or neglected. Honda it seems were more interested in the fuel consumption than performance. Dohan and Kokinski weren't interested at all.
Fuel injection software and hardware has also moved on a lot.
It almost reminds me of the 3m post-it story.

Spencer Ferguson Silver is an American chemist who, together with Arthur Fry invented Post-it notes in 1970
I had thought about it, I wouldn't have done the experiment. The literature was full of examples that said you can't do this

In no way am I mocking TeeZees efforts, absolutely the opposite.
He is doing all this wrist slashing in public, and I admire the efforts, just trying to suggest concentrating the limited time, we all have, on a fix for the deto issue.
Variable inlet, EFI etc will for sure soak up a heap of R&D time.
I made the same ( negative, sorry ) comment about CVT, but shit, if you think im starting to hold hands with SS90 on here, then I will shut up.

please no more thought of a relationship with SSunamable

[F5 Dave]

. . .. Honda it seems were more interested in the fuel consumption than performance. . . .

Hadn't they achieved the fastest top speed on (erm was it Aoki's) one? Sounds performance based.
[edit I've had to become Husi & had to Google it for completeness, : it was Itoh)

[F5 Dave]

. . .
[edit I've had to become Husi & had to Google it for completeness, :. .

oh Nos, the transformation is complete;

from same NSR site
"Doohan prefers to keep things simple, he wants to win races not develop motorcycles and his tireless efforts at weaning HRC off their high-tech fantasies have been largely responsible for the NSR's success. He only improves things when they need improving.. . . ."

Wob's points compressed?

+
"For '97 Doohan decided he wanted to run a 180-degree motor. HRC didn't like the idea but he was mighty fast during first tests, and when Criville tried the screamer it spat him off at 120mph. Doohan knew he could regain an advantage with the engine, for engine management technology made it more rideable than the old 180-degree V4s and tire technology had caught up too. Plus the screamer sounded so much better".

Well yes it did sound awesome seeing (hearing) him exit out of Lukey Heights & the soundtrack it laid down.

maybe this should be next point of TZ's development? Aural output?...erm input, whatever.

[Flettner]

To be fair, I do wonder that using E90 gives me a little wider fueling range. E90 is not like Methanol where you almost can't be too rich, E90 will certainly blubber when rich and lean, well that's not too desirable! E90 has an unusual feature of requiring more fuel as the engine get's hotter, it will lean out. The EFI has the nice ability to be able to map this and change fueling with temp. Interestingly I haven't damaged a piston since using EFI.

[husaberg]

oh Nos, the transformation is complete;

from same NSR site
"Doohan prefers to keep things simple, he wants to win races not develop motorcycles and his tireless efforts at weaning HRC off their high-tech fantasies have been largely responsible for the NSR's success. He only improves things when they need improving.. . . ."

Wob's points compressed?

+
"For '97 Doohan decided he wanted to run a 180-degree motor. HRC didn't like the idea but he was mighty fast during first tests, and when Criville tried the screamer it spat him off at 120mph. Doohan knew he could regain an advantage with the engine, for engine management technology made it more rideable than the old 180-degree V4s and tire technology had caught up too. Plus the screamer sounded so much better".

Well yes it did sound awesome seeing (hearing) him exit out of Lukey Heights & the soundtrack it laid down.

maybe this should be next point of TZ's development? Aural output?...erm input, whatever.

Aim higher i didn't google it, but it was in a Mag. The injected bike was Itoh the speed differential was simply explained as he was a rather little japanese bloke (plus he wasn't half crippled and he could tuck in tighter.)
Yes your transformation to the dark side is Nearly complete.
But first you have to snog your sister and i get to cut off your hand..
RE the noise why not. the noise of the 2 smokes harassing then passing an Fxr on Yows on bike video on the FXR150 site..... pure music.

Note for the real Anoraks Itoh rode the injected bike for part of the season. But his best result of the year was his one of ride on the injured Doohan bike.
Faster top speed might not necessarily lead to fast laps........ Remember the Gardner San's missile.....
point ot remember is the packaging on a fuel injected bike also offers some other advantages edp on the v4's
Follow the arrows for the attachment

Itailian Friday

Few could deny it is still a beautiful bike.

It was on the cusp of finally living up to its potential.
Finally being developed in a more methodical manner.
A great shame the plug was pulled.

I found this snippet of information whilst looking for Rs125 specs.
It would appear to have come from Shigeru Hattori NSR500 project leader. I am now more confused than ever about how it worked.

Also here some Honda stuff whats the secret HRC

[TZ350]

In no way am I mocking TeeZees efforts, absolutely the opposite.

He is doing all this wrist slashing in public, and I admire the efforts,

just trying to suggest concentrating.

What are you trying to tell me ……




The deto in over rev cylinder thats currently on the bike is the 28hp "B" cylinder, with single exhaust port (Green line).

I suspect the real problem with the 28hp cylinder and over rev deto may be insuficent blow down time area, but to increase that, I fear the curve will become more like the Purple 30hp line.

It would be great to get the "B" cylinder working properly if the curve could be kept flat. So Wob if there are any simple suggestions that have been made that I have overlooked trying, I would love to be reminded about them.

The 28hp curve is nice and easy to ride and if its not to hard it would be good to get it working properly, but its not my primary focus, a ridable 30+ hp is.

The real R&D effort is going into improving the bottom end of the tripple exhaust ports 30hp curve, Purple Line.

EngMod2T tells me that I can have both, a much wider flat torqe curve than the 28 and more than 30hp, and I want it all.



Side exhaust port power valves and better fueling and breathing are the order of the day. In acheving that, the over rev deto problem will probably resolve itself on the way.

[TZ350]

The EFI has the nice ability to ... change fueling with temp. Interestingly I haven't damaged a piston since using EFI.

And crunching numbers on a laptop beats shagging about with jets at $9-$12 a pop and a carb thats a prick to get at (like most bikes) anytime.

There is a lot that is attractive about EFI.