ESE's works engine tuner

[Frits Overmars]

NF4 never had water under the exhaust, from the factory (had right angled press in inlet) . The cases can be modified to send the water up under the exhaust duct.

You're quite right; I corrected my post. Below is a standard NF4 engine.
When taking a (too) quick glance through my Honda-stuff, I noticed an NF4 with water from below, but now it turns out to be the modified engine from Dutchman Hans Spaan, one of the very few riders deemed worthy of a Honda A-kit.
Honda used to have the mechanics of those riders come to Japan in order to assemble their bikes under HRC supervision. When Spaan turned up, he was assumed to be such a mechanic. The Honda-people were astonished that he could not only ride fast enough to be vice-world champion, but that he could also work with his hands.

[Michael Moore]

When Spaan turned up, he was assumed to be such a mechanic and the Honda-people were astonished that he could not only ride fast enough to be vice-world champion, but that he could also work with his hands.

Similar to when Sammy Miller was picked up by Honda and at a test ride at the factory rode it a bit and came back and took a hacksaw and modified the frame so it would steer better. The story goes that all the high brass onlookers were horrified/amazed.

[lodgernz]

Pavel, you have pretty tight ratios for three speed moped, I thought it would be much wider. That green rider's bike is slowing down from lap to lap but he has much less mistakes than you..
Glad to see good moped race.
This is how Slovenians prepare 60cc tomos six speed engne, my friends bike,just love to hear this bike singing from time to time
https://youtu.be/XrjUK2431pk

Wow! What a great street race. Fastest bike in that race by a good margin. Any tech details of the engine?

[Michael Moore]

I was recently looking at some information on the Athena GET ECU for the Flettner, excuse me, KTM TPI 2T singles. I was surprised to see that in the "Race Kit" they relocate the injectors:

https://transmoto.com.au/product-get...-injector-kit/

GET has also released an “ECULMB Race Kit”, which includes the ECULMB control unit and an injector support kit for KTM’s 250/300EXC TPI and Husqvarna’s TE250/300i.

Interestingly, instead of using KTM’s patented TPI technology (where fuel is injected into the barrel’s transfer ports via two injectors, rather than directly into the combustion chamber), the ECULMB Race Kit’s injectors are positioned between the cylinder and the throttle body – a change that, according to GET, helps bolster power across the rev range, but especially at low and medium RPMs to improve rideability.

TPI makes so much sense, I'm having difficulty figuring out why moving the injectors to a more traditional location would give improved power/rideability. Does anyone have an idea on that?

thanks,
Michael

[yatasaki]

Black graph is bike on 2:35 with no.81 tomos 5 gear 60cc cast iron cylinder with dellorto 24
Red graph. 6 gear Tomos 60cc cast iron cylinder,piston ported dellorto 26 bike which was recording. Tuned by same guy.
You can see me as well on 2:35 with no.42, pity, I was leading the race, but piece of clutch ended in gear selector, 3rd at the end but with no clutch problems would be very hard to keep up with bike recording . Very sleazy street track

[husaberg]

I was recently looking at some information on the Athena GET ECU for the Flettner, excuse me, KTM TPI 2T singles. I was surprised to see that in the "Race Kit" they relocate the injectors:



TPI makes so much sense, I'm having difficulty figuring out why moving the injectors to a more traditional location would give improved power/rideability. Does anyone have an idea on that?

thanks,
Michael

I have a theory. But not sure i have a clue
Honda pursued Fi for power (with the hope of better economy to boot) as did Cagiva they both ended up with Port or throttle body injection.
Both hoped it may have lead to a more compact engine carbs take up more room between the V and cagiva thought it might have allowed the use of disc valves later on.

Di was also banned in 500 Gps i think anyway
Honda had already tried some sort of Cylinder or crankcase transfer port injection in the 70s on the RC125's but it was crap then( likely mechanical. )I have this from two sources one of them was someone who had to ride it.

You can be pretty confident before they settled on the NSR500 and EXP system they tried hundreds of different ideas but their main aim was power with better economy.
Honda also raced a 250 in the 250 japanese champs for a few years prior to Itos season on the NSR500
Here is the first ever pic i have found of its engine set up. Its called the RS250RW
heres the std one https://blogimg.goo.ne.jp/user_image...05dfea357c.jpg
Evitrude and orbitial etc went for emissions and economy etc and ended up DI.
Flettner went for what he could get to work and and decent performance driveabilty.
ktm tried them all, But they were after emissions with the same power they couldn't get DI to make decent power so they just copied fletner.

[katinas]

Thanks for advice Katinas. Easy to follow it! I making big parts for pistons need order correct material like AA2018 AA2218 AA2618
Or may be for CNC mill without forging there is better materials...

Long time ago, for pistons we used heat resistant AK-4 alloy ( used in jet engines with Fe and Ni ) very similar to 2618, but of course you must know.
Now I tested only 2618 T6, just what I can get. Made from peace, without forging and after run in, pistons works fine. There is 2618A, but little different composition and little more expansion, but more resist to cracking.
From castings alloys, I remember low expansion AL-26, maybe very similar to 4032, but more fragile than 2618. Of course now days maybe exist better special alloys.

Just remember, long time ago I prepared IZ Planeta Sport 340 for road racing (add photo of original and modified for race ). We got some aftermarket cast pistons made from old bus diesels engines pistons, with much silicon ( from my memory it was from Ikarus bus ). They never seized, even with zero clearance on friends engine ( he must put piston with force to cylinder when assemble and I cant believed that he use this engine without any seize). The best things about this original motorcycle, was that frame was made from CrMo like front fork tubes and upper triple clamp with fork lower legs made from B-95 alloy similar to 7075.

But once, with my race modified version, on the straight, when engine revs up little longer at nearly 10000 rpm (with 76 bore and 75mm stoke) all ended with catastrophe bang. I didnt release what was first, conrod or piston, but conrod flying out of the engine and I left with aluminium- silicon sand in my handful.

Honda, for some GP two stroke pistons, used casting AC8A-T6 alloy with max Si 13 %, Ni 1.5 % and Cu 1.3%. https://patents.google.com/patent/DE60208944T2/en

[katinas]

Honda also raced a 250 in the 250 japanese champs for a few years prior to Itos season on the NSR500
Here is the first ever pic i have found of its engine set up. Its called the RS250RW

Thanks Husa, indeed first ever...

[jbiplane]

Long time ago, for pistons we used heat resistant AK-4 alloy ( used in jet engines with Fe and Ni ) very similar to 2618, but of course you must know.



Honda, for some GP two stroke pistons, used casting AC8A-T6 alloy with max Si 13 %, Ni 1.5 % and Cu 1.3%. https://patents.google.com/patent/DE60208944T2/en

Thanks for so detailed answer. Will educate all stuff you sent

[Pursang]

Play-doh seems a bit childish & impractical
Here is a commercial product that might allow the exhaust gasses to pass right through the duct into the chamber, without leaving behind a lot of heat to warm the fresh charge.



Unlike a Tin or Ceramic coffee cup, the carbon foam replicates the thermos flask:
Reflective/emissive contact surface, long heat paths and minimal conduction and convection.

And if it all seems a bit too "Space Age" remember that V-2 rockets were using graphite vanes in the exhaust nozzle, way back in 1944.
Aircraft & F1 have been using carbon brakes for around 50 years.

Cheers, Daryl.

[Pursang]

In 1994 Lockheed did some successful development and testing work for NASA on Carbon Carbon Composite pistons.

https://ntrs.nasa.gov/archive/nasa/c...9940031440.pdf

Biggest problem they found was that the air cooled cylinders expanded more than the pistons did.
This opens the opportunity for CCC cylinders, some work has been done on these.
Carbon Carbon matrix has also been used to provide for highly efficient liquid cooling of computer chips.

Once again that was pretty much rocket science back then. Highly specialised and incredibly expensive.
Now we can design & fabricate n-dimensional fibre matrix patterns to achieve whatever physical properties are required for an application.

Items can be molded, printed and/or machined. There are dozens of US & Chinese companies touting on-line for the fabrication work.

cheers, Daryl.

[katinas]

If I remember correctly, CC pistons was used on RC models engines, but some chipping at the top edge, limited using them.

[Pavel Myslik]

Pavel, you have pretty tight ratios for three speed moped, I thought it would be much wider. That green rider's bike is slowing down from lap to lap but he has much less mistakes than you..
Glad to see good moped race.
This is how Slovenians prepare 60cc tomos six speed engne, my friends bike,just love to hear this bike singing from time to time
https://youtu.be/XrjUK2431pk

The gearbox is not original. Fortunately one guy in my country makes these for very reasonable price. The green rider has more experience and even I am able to be faster than him sometimes, he is more consistent and has excelent starts. This was the second race of the day and I managed to beat him in the first so it was a tie.
Hats off to your friend, It's really singing nicely.

[guyhockley]

I see the Ryger has moved to the next, logical phase of its development...

https://youtu.be/6M9Yqctk_Tg

http://www.ridders.nu/Webpaginas/pag...t_frameset.htm

[F5 Dave]

I thought when the video started i thought it would be some fancy coffee machine.

70hp coffee anyone? Where do I send money to invest?