ESE's works engine tuner

[Frits Overmars]

Frits
I thank you for your reply and, as always, look forward to more of your wisdom both said and unsaid. I just have to train myself to read the unsaid parts a little more diligently.
If I may comment on your 'Leaning Tower of Pisa' treatise. It was the most comprehensive writing I have seen. I have a pretty good little library on 2T engines and none of them could explain the workings of a 2t as well as what you wrote, at least that I could understand. Many thanks.
wobbly
Thank you. That info and what Frits said (and didn't say) gives me some parameters to work with in JanBros's excel sheet.

Jeff, thank you for your kind words. Now I wonder: what is it that I 'didn't say'? Are you perhaps referring to information in pictures ?

EDIT: I think I got it. Were you alluding to "The placement of the intersection point with the bore center line was not mentioned at all in my scavenging concept" ?

[lodgernz]

A slight umbra sheen tells you it's nicasil, as does the lack of a perfectly round separation line.

Thank you Andreas. Anyone else care to comment?

[wobbly]

It must be a nicasil , as the spigot is fully coated on the end , but the bore edge at the transfer ducts is " ragged ".
I ssume also they have taken the chrome flash off the top deck as that is only a narrow band.

[lodgernz]

It must be a nicasil , as the spigot is fully coated on the end , but the bore edge at the transfer ducts is " ragged ".
I ssume also they have taken the chrome flash off the top deck as that is only a narrow band.

Thanks Wobbly.

[SwePatrick]

Can it be explained by friction ?There is a thermodynamical small gain going from 15 to 16 but there is also a at least 6% rize in friction from the piston ring

I dunno actually.
But those 6% increase might not be comparable to engines total friction.
Say the ring stands för 2% of engines total friction.
And 6% increase of those 2% isn´t much at all, 2.12%

[jfn2]

Hello Frits

Now I wonder: what is it that I 'didn't say'? Are you perhaps referring to information in pictures ?
EDIT: I think I got it. Were you alluding to "The placement of the intersection point with the bore center line was not mentioned at all in my scavenging concept" ?Yes, I was alluding to that. If this intersection point was of no significance why did you place the 'Trailing and Leading Distances' markers on your drawing? I just thought that the placement of the column in the bore would be critical to all the other measurements. I understand that the 'position' angles are very important also to achieve this intersection point but since about 99.6% of us are trying to change existing cylinders it's not always possible to change where the ports are located to the extent needed to achieve the 30* angle. Therefore my question...Which is more important, the angle of the leading edge or the intersection point on the bore center line? I also understand this is about reducing the short circuiting problem. I'm just trying to do the best I can with what I have to work with. Thank you very much for all of your help. We keep plugin away.

[TZ350]

I had to draw pictures and high light stuff to get my head around this.

Pic 1. As more power is developed, a hole/dip (Point B) appears in the the power curve just before max output (Point A).

The drivability of the bike is affected by this dip just before max power.

There is a trade off between power and drivability. (as we all know)

The main things that make more power, are, and in order of priority (1) the primary transfer tangental angle, (2) the inner transfer port radius, (3) the main transfer port axial inclination, (4) and main transfer port open size and shape. All high lighted in pic 2.

Pic 3 data from tests that show the trade off between power and drivability for the different variables.

Pic 4 configuration of the better test cylinders.

Get a copy of the paper from here:- http://www.2stroke-tuning.nl/media/pdfjes/porting.pdf

.

................

[TZ350]

Here is a little technical story for the coming Christmas days. Its official title is Transfer Theory, but I call it

The leaning tower of Pisa


Transfer theory part 1

the central column

..............

Originally posted by Frits

[Frits Overmars]

If this intersection point was of no significance why did you place the 'Trailing and Leading Distances' markers on your drawing?

I did it to show the coherence between the old way and my way (do I sound like Frank Sinatra?), like it says in the Leaning tower of Pisa-treatise:

Most two-stroke people define radial scavenging directions by quoting the distances where the ports would intersect the center line (the leading distance and trailing distance in the drawing below left). Gordon Blair used that notation in his publications, and 95% of us followed suit. But there is a better, more universally applicable way.

[husaberg]

..............

Originally posted by Frits

some of my best writing
of my Plagiarised content anyway...

[jfn2]

Frits
Again thank you very much for your reply and patience. It's finally beat into my head.

[TZ350]

.
2Stroke Stuffing's adventures continue. Getting the 24/7 engine running for testing the dyno. https://youtu.be/7ShU3YnFOpw
This so very much reminds me of what a lot of people at the sharp end go through developing their bikes for "Bucket Racing".

[Vannik]

.
2Stroke Stuffing's adventures continue. Getting the 24/7 engine running for testing the dyno.
This so very much reminds me of what a lot of people at the sharp end go through developing their bikes for "Bucket Racing".

He is now discovering why most development is incremental, and even then you can get very lost. Making a paradigm shift is sometimes very challenging.

We are all holding thumbs he finds his way!

[Ns1Montesa]

I'd like some advice please from the more experienced tuners here. Would you say this cylinder has a steel or cast iron sleeve, or is it Nicasil?

Sorry for the poor photos, they are the best I could get, and as it's a Japanese wesite, of course there's no information except what engine it fits.

Attachment 350199Attachment 350200

This cylinder looks like a alu clone of the nsr75/ns1 (47,5mm bore) cast iron ones. The Bikes were mainly sold in spain.
Lodgernz, do you have a link to the homepage where I can find these cylinders?

Greets

[lodgernz]

This cylinder looks like a alu clone of the nsr75/ns1 (47,5mm bore) cast iron ones. The Bikes were mainly sold in spain.
Lodgernz, do you have a link to the homepage where I can find these cylinders?

Greets

Actually made for the NSR80 & CRM80, but will fit perfectly on the NS-1 75cc crankcase. It will require the corresponding 49.5mm piston.

https://japan.webike.net/products/24635158.html