ESE's works engine tuner

[Flettner]

I came to the same conclusion some time (40 years) ago which resulted in my FOS symmetric scavenging system.
Here is a picture that you may have seen in another forum a while ago Neil.
Attachment 353851

Thankyou, Ive cleaned out the pattern shop ready for another cylinder construction, for a water cooled twin port 125, a little more serious attempt this time, 54 x 54.

[wobbly]

Neil , please explain what advantage you are hoping to attain with a twin duct setup connected to a T port.
To me all it does is add a shit ton of circumferential wall area , for the same effective diameter , then you have to contend with a 2:1 header , or run two chambers.
Why - Jawa did it a million years ago and how may titles did that POS win.

[husaberg]

Why - Jawa did it a million years ago and how may titles did that POS win.

Jawa won a few
but then went to centre port and won some more

[Grumph]

Jawa won a few
but then went to centre port and won some more

Ha - I've ridden both in competition. The twin ports were much nicer to ride.

But that's in relation to the levels of suspension and the tyres of the period.

[yatasaki]

Ha - I've ridden both in competition. The twin ports were much nicer to ride.

But that's in relation to the levels of suspension and the tyres of the period.

Bike was killer for corners, making lap times better than some morinis and RDs from higher classes..on shorter tracks
But as you can see, engine itself wants to get rid of second pipe.

[Flettner]

Neil , please explain what advantage you are hoping to attain with a twin duct setup connected to a T port.
To me all it does is add a shit ton of circumferential wall area , for the same effective diameter , then you have to contend with a 2:1 header , or run two chambers.
Why - Jawa did it a million years ago and how may titles did that POS win.

Your comment on Bridged port " the more the hook on the edges of the port the better they go " makes me think if you take that to its end game, the more direct the outlet from each port the better the gas flow.
Plus, way back then they had shitty pipes and terrible transfers and direct air cooling.
Time to re visit it? With a twist on the standard concept ..... should give a lot more blowdown area.

I know it means nothing but my my little AG seems to go alright.

Let the debate begin.

[Javier Ruda]

Today I have just noticed that after chopping the throttle at high engine speed, the egt sensor shows a spike of ~20 ºC for about 2 s, and it is not a fast probe.

Is it normal?

That let me thinking about the pilot jet, but I think it is OK at 1.5 air screw turns.

[wobbly]

I would guess that as you roll off the throttle , the needle/tube annulus area is too small , and this is of long enough time duration to be shown on the data log.

[katinas]

Some testing with silencer reed valve. At first it was interesting just to try, honesty without too much hope. But after back to back tests always return to them and continued testing other things just with them.
There is no feel any difference at mid range, but feels little stronger when engine is on the pipe.

https://youtu.be/YRVyc8Mja0o
https://youtu.be/g0WVwmgPLGs

[Javier Ruda]

I would guess that as you roll off the throttle , the needle/tube annulus area is too small , and this is of long enough time duration to be shown on the data log.

Thank you wobbly. I think you are right. For better progression I reduced the annulus 1 point (needle +2, diffuser +1). I didn’t know that it could affect the throttle closing. It is a bit scary so I will revert it and check again.

[F5 Dave]

Thank you wobbly. I think you are right. For better progression I reduced the annulus 1 point (needle +2, diffuser +1). I didn’t know that it could affect the throttle closing. It is a bit scary so I will revert it and check again.

An old mate used to say "2 Strokes only seize on a closed throttle "

Let's not ponder the accuracy of that, but it certainly is food for thought. Perhaps with a side of supplementary Injector in the cases to prevent that lean blip.

My Air-cooled Honda 100s were keen to nip up only on long tracks if I wanted a clean running pilot fitted. But thermal compromise.

[katinas]

Not this one because its air cooled.
By having two smaller exhaust ports, with extensive water cooling atound the ports and a heavily cooled bridge area, has to be better at keeping 'exhaust charge' cooler?

How much work has been done on twin port exhaust with water cooling, modern transfer layout and up to date exhaust design?

If we are in fact after maximim blowdown time / area.

Old cylinders from useless engines, but not because of two exhaust ports.

With this configuration exhaust orient directly in front of B transfers, maybe this needed some attention.

[husaberg]

Didnt Kensational buld a twin port it was posted on Pitlane?

Neils, this is me Ken Seeber, more commonly known as Kensational.

It .

[Javier Ruda]

An old mate used to say "2 Strokes only seize on a closed throttle "

Let's not ponder the accuracy of that, but it certainly is food for thought. Perhaps with a side of supplementary Injector in the cases to prevent that lean blip.

My Air-cooled Honda 100s were keen to nip up only on long tracks if I wanted a clean running pilot fitted. But thermal compromise.

Absolutely. I only have seized on coastdown or a gear change.

Maybe a leaner slide could help, because it can improve the progression without leaning the pilot or the air screw or the needle tube. I think that the slide should have no effect or little effect at closed throttle, but who knows. I will check if the egt spike continues to happen.

[a.montani]

The factory deleted the water entry up under the Exhaust duct completely with the R1 , as this means the duct heats all the cold water before it runs over the transfer tops.
The 10B and 10C they added a side water hose to push cold water over the duct top only.
The best solution is to use an extended spigot over the top of the duct with holes pointing back over the transfers , and have 2 x3mm holes up from the case to keep some flow
travelling up to the head.
Thr R2 has my spigot extension within the casting , it just needs the 3mm holes to move water around the duct from the case.
This can also be done to a Vortex , as it has a threaded hole in the cylinder - the CIK have confirmed to me in writing this is legal.

Hello to everybody.
My name is Andrea (53 yo) and I am a mechanical engineer living in Italy.
In the middle of july I started to investigate (helped by Neels) how cylinder and engine case cooling impact on 2 stroke engine performances.
Info by wobbly are clear, cold water goes to cool transfers by the 2 holes on the spigot, while duct roof is cooled by other holes. Isn't it?
Is it possible to get other pictures of the spigot and the duct cooling case showed?
In this cooling system how TM manage water flow around the duct (duct floor)? Water exit is always on the cyl head. How is the water flow around the duct?

What about cyl head cooling? Are there any concerns lowering temperature of the head dome? And squish area?

What happens if I let cold water in through the head (currently the outlet) and out through the current inlet?

This is the first time in this forum, if I did something “wrong” please help to avoid this in the next posts.

Grazie 1000 and Regards
Andrea