ESE's works engine tuner

[Dutch Fisher]

I remember the problem, but it hasn't bothered me lately .

First they were works Honda NSR250, then they became Honda RS250 kit and RS125 kit, then they became standard.
Then they appeared on the works reed valve Derbi 125 (tuned by Harald Bartol). Then they appeared on the 125 and 250 cc works KTMs (tuned by Bartol).
Then they appeared on the KTM production racers.

Now now Frits your surely not saying that the later half of Harold Bartols career was little more than a plagiarizing exercise involving paying a poorly paid mechanic from a team that ran A-kit Honda equipment the equivalent of say US$3500 to either accuately measure pipes and cylinders or indeed arrange a hour or so of time for an associate of the afore mentioned Herr Bartol to have in hand the afore mentioned A-Kit cylinders by which the associate may if he so wished to take a silcon cast mould of transfer and exhaust shapes and angles.

How dare you Sir !!

That is a bit like saying in 1999 that Yamaha did such a similar act of midnight espionage with the assistance of a similar poorly paid mechanic for the exchange of a similar fiscal amount (adjusted for inflation) in time to power their champonship winning Y2K 250 racing motorcycle and then produce a fabrication of a story that hints at their success being down to a newly acquired Chech made CNC controlled anemometric-tester machine and a change to 54/54mm bore/stroke ratio that is it just so happens to share with say an A-Kit Honda.

I myself will not hear of such a thing in the arena of sporting gentleman where honor and valour are upmost and peeking over an opponents shoulder would never enter the mind of such esteemed competitors.

[wobbly]

I dont get what the issue is here.
The A kit pipe dimensions were published by Honda very early on, and those dimensions were used by Harold,when he was developing his own cylinders whilst still working for the Yamaha 125 effort (with Ui ).
In fact talking to him at the time it was almost as if he was proud of the fact that he had used the same pipes for 3 years or so.
I offered to do something better, but was politely told no thank you.
And as Frits says, those same dimensions then went to Derby, where later Jan blew Harolds best work into the weeds.
Then those same pipes appeared on the KTM, a superbly conceived piece of engineering, but certainly not the fastest - again I thought it a travesty that those old dimensions were stuck to for some weird reason.

Then we have another rant about the champ winning Yamaha 250.
That engine used the new cylinders developed for the 500, and that certainly derived its performance from what the engineers learnt from the Czech machine ( Bud Askland got one first when tuning for Kenny/Rainey )plus the conversion to 54/54 - that was an obvious need.
Honda had no more influence on any of this than say Aprilia did, it just became obvious that sticking with corporate pride and a 50.6 stroke was dumb from the start.
Sure it was a very complete, well developed machine, but after years of the TZ being laughable, it for sure was the new technology in the 250 engine that made the real difference - with the addition of the superb Yamaha developed spool valve from the ancient YPVS.
Whats the problem.

[kel]

another rant about the champ winning Yamaha 250.

Good old Yamaha, but then “Imitation is not just the sincerest form of flattery - it's the sincerest form of learning.” They really should have credited Honda in the references though

[Frits Overmars]

“Imitation is not just the sincerest form of flattery - it's the sincerest form of learning.”

I must disagree Kel. If you perfectly copy a perfect solution, it will work perfectly but you won't have learned anything.
I keep saying: "Everybody has to make their own mistakes". That means 'gather experience'.
But I also say: "Try to learn from other people's mistakes because you won't have time to make them all yourself". That means 'Listen. Look. Read. Get an education'.

[seattle smitty]

Motor-racing is fascinating partly because it has many components, many subtleties. If the competition only consisted of "dyno-racing" engines against each other, the various engine questions that are covered in this thread would pretty quickly be settled. But instead, the racing involves riders/drivers on bikes/karts/boats/sleds/etc. powered by engines, set up by tuners of engines. The best engine doesn't always win. Nor does the best rider, nor the best bike.

Bearing on the study, knowledge, practice, and experience called for above, is applied intelligence (alas for me!). In reading about Kenny Roberts, for one example, I've been struck by his ability to analyze a track, the ways he can set up his bike to work with the track, and the ways he can ride the track to gain an edge over competitors, whom he also studies. He didn't win on sheer natural ability; there were others more talented. (I never met Roberts, who used to have a reputation as a "prickly" individual, but I like him because he is not just a rider but an all-around RACER who can weld and run machinery and build his own equipment. A.J. Foyt is another such).

Motocrosser Bob Hannah said the same of himself, that he had to out-think others to win. After leaving motocross, Hannah did some air racing at Reno, and now flies bush planes for fun. But he hasn't stopped thinking. His wife tells of riding along over wild country and suddenly challenging him by suddenly saying, "Engine out, where do you put us down?," and every time Hannah will instantly point out the window and say, "There!," and tell her why, because he is always watching the terrain and thinking about it.

Maybe some of you have read Keith Code's books on improving your riding and racing. He also make a strong case for bringing intelligence to bear on the problem. It is good to get plenty of track time, says Code, plenty of practice, but it is far better that you get GOOD practice, intelligent practice. Don't just ride the track, THINK about it, test ideas, have goals, figure out what's happening and why, get the most out of the practice.

Much of the fun of this thread is watching everybody applying their own intelligence, crunching information in their cranial computers, trying to figure things out.

( blah, blah, blah . . .)

[Yow Ling]

I must disagree Kel. If you perfectly copy a perfect solution, it will work perfectly but you won't have learned anything.
I keep saying: "Everybody has to make their own mistakes". That means 'gather experience'.
But I also say: "Try to learn from other people's mistakes because you won't have time to make them all yourself". That means 'Listen. Look. Read. Get an education'.

Sucess is a poor teacher

[Grumph]

Sucess is a poor teacher

It pays the bills and keeps sponsors happy though...and may just get you enough time and money to do the experiments you have lurking in the back of your mind.

[Frits Overmars]

Sucess is a poor teacher

Right you are, Yow Ling. It only taught me that champagne and contact lenses don't go well together.

[peewee]

hey guys sorry if this is a dumb question but whats the easiest way to tell if a crankshaft is forged or cast ? ive heard you can easily tell by the parting lines where the molds or dies meet but from looking at the couple cranks i have in the garage it doesnt appear theres any parting lines, so im thinking they must have been on the circumference of the wheels. since the circumference of the wheels are machined , any parting lines would be gone. i have a few cylinders sitting around and the parting lines from the cast molds are easily seen but the crankshafts i have i dont see these lines. thats why im guessing they were at the circumference of the wheels which have been machined as the final procedure during manufacture. from what ive read (and seen on cylinders) cast will have thin sharp parting line. forged will have wider dull parting lines. but like i said, how do you tell what crank it is if there is no visual parting lines ?

[crbbt]

Thanks for the response Frits!

More information than I could have hoped for.

One of the mechanics on the weekend at philip island reckon he could wind up the 125 to blow the moto 3's away! I don't yet have the ability to keep on it.

[TZ350]

Sucess is a poor teacher

"Failure" I must have a good teacher, because I now know far more about running a 2T with EFI than I wanted to .....

[Dutch Fisher]

Right you are, Yow Ling. It only taught me that champagne and contact lenses don't go well together.

Frits you are supposed to drink it, not pour it in your eye

[RAW]

Various copies of Jans aprilia exhaust port profiles

[Frits Overmars]

Various copies of Jans aprilia exhaust port profiles

Maybe you swapped the DEA and VM captions?

[oktrg500]

Hi,

The following I'm unable to understand. The subject in speak is the air box for the Aprilia RS 125 streetbike. Reliable sources has reported several times about loss of power when the 'snorkel' is removed. I'd like to understand why. Understanding why, would be valuable when trying to figure out if the std design can be improved upon. Attached is an exploded view of the box, which I've tested holds 2,4 liter of water. And a back to back test in the dyno from the internet with and without the snorkel.