ESE's works engine tuner

[husaberg]

RGV 500 pipes

https://www.ebay.co.uk/itm/Suzuki-RG...0AAOSwIzBaycAQ

https://www.ebay.co.uk/itm/YZR500-50...oAAOSw27FbPIW6

Cheers i flogged a few pics as well as the crank one i didn't already have.
Note is this the tungsten inserts edge welded in.

The colour i guess is the copper coating?

Note the Crank is also 90 Degree's plus the seller saus it has 3VX rods so the sizes are the same or similar to the late TZR V twin.


Here is a 180 Cagiva for comparison
plus some case pics

Cagvia Case
Yamaha YZR500 case

[Niels Abildgaard]

Cheers i flogged a few pics as well as the crank one i didn't already have.
Note is this the tungsten inserts edge welded in.

The colour i guess is the copper coating?

It is most likely a 10% cupper-90 % wolfram alloy.
It is easy to machine and almost as heavy as pure wolfram.
It is used by the spark erosion people

[Dutch Fisher]

The colour i guess is the copper coating?

It is most likely a 10% cupper-90 % wolfram alloy.
It is easy to machine and almost as heavy as pure wolfram.
It is used by the spark erosion people

You sure that's not the copper plating used on cranks to to mask off areas where metal treaters don't want the nitriding process to act on?

[Norman]

Pictures attached, but it seems I am not capable of doing the translation.

Looks like those pics got deleted in the melt down the other day.


Here's a scan i got off the german 2-takt website, i've translated the jap to english.

[Norman]

Interesting with the heat isolation material there..If the engine is tuned at the dyno lab with a "low flow" air fan and then used on the track with the high air flows that one would expect to hit, especially the header, will no the exhaust gas have another temperature and the tuned length become out of phase compared to the dyno calibration? As I understand, as the exhaust port opens, the flow is very turbulent and the heat transfer to the walls in the exhaust port and the header/exhaust is high. Also thinking about Mr. Jan Thiels statement that the internal cleaned exhaust decreased performance a bit until a new carbon layer was created.

RGV 500 pipes

https://www.ebay.co.uk/itm/Suzuki-RG...0AAOSwIzBaycAQ

https://www.ebay.co.uk/itm/YZR500-50...oAAOSw27FbPIW6

[flyincat]

Wobbly - I'm interested in learning more about the EGT vs jetting correction you preach, over and over, regarding dyno testing. You've stated numerous times about re-jetting after a change to get the EGT back to where it was before a modification. What I can't seem to find is much reference to the air fuel ratio (AFR). Could you say a few words about the affect on AFR when making these jetting changes to maintain a target EGT? Is re-jetting bringing the AFR back to where it was, along with the EGT? I hope the answer is YES because then I understand. But, coming from EFI and lambda sensors, I have a nagging thought that a jetting change = AFR change. In that case, the balancing act between AFR, ignition timing, detonation, EGT, etc. would need to be revisited as a whole, no? You don't seem to mention revisiting ignition timing and affects on detonation in your 're-jetting for EGT' warnings, so thought I would ask.

[wobbly]

Yes Dutch - the copper coating is used exactly for that process in heat treat.

Re the egt preaching lesson.
EGT in the header is a metric of the resultant wave speed in the pipe , due to the average gas temp along its length, plus the radiation rate thru the wall area.
One of the most important variables in a racing two strokes performance is the interaction of the wave speed with the pipe length.
I have done enough testing of the TM - KZ to know that best power temp for that pipe is 640*C , and from that result and knowing the RAD on that day I then have a graph to predict
the jetting for any weather at any track.
All you are doing by insisting on a baseline egt number is correlating the jetting to an optimum BSFC.
Less air needs less fuel = less Hp on the day, but the best power egt remains constant.
Anything that changes the egt ( weather, trapping efficiency due to porting etc ) will change how the pipe reacts - more so than the change itself.
So in answer to the question, as there is a direct correlation between egt and A/F ratio you would need to do the same process as I have done.
Find the best power A/F number and shoot for that every time.
BUT , every test MUST have the same pipe and water temp ,at the beginning and end of each pull , or the results are erroneously affected by the differing temp ,NOT the change you have made.
I could go on for another 5 pages about this , but you all will be bored by now anyway.

[41juergen]

Hey Wob, never boring! It's ike the desert when coming back from lunchtime into the office...

[teriks]

I could go on for another 5 pages about this , but you all will be bored by now anyway.

No way I'm bored by your in depth information/discussion of two strokes, 5 pages wouldn't be even close! 500 pages on jetting alone then maybe...

[husaberg]

Yes Dutch - the copper coating is used exactly for that process in heat treat.
.

What did you think of my Theory that the Honda NSR500 BIG bang was just a 90 degree doubled up v twin Wob?
In that 68 Degrees Honda spoke of was just the offset to make it a 90 degree twin on account of the 112 degree V.


Also that last pic i posted did you notice the hollow pin on the left crank-wheel next to the welding locked in with peen, i first thought it was a pressed in mainshaft but its not in the middle. why would they use a hollow weight pin that far inboard, a mistake or modification?


the other pic shows it as well from the other side.

[190mech]

Perhaps its a locking dowel to keep the crank from twisting like the ones you posted at #2369 in the "oddball engines"
thread?

[husaberg]

Perhaps its a locking dowel to keep the crank from twisting like the ones you posted at #2369 in the "oddball engines"
thread?

it Just seems way to big ,but it is parallel with it though?

[katinas]

Add some drawings from "Racers" that can be helpful about YZR, NSR "Crank-angle-firing-forces".

[flyincat]

All you are doing by insisting on a baseline egt number is correlating the jetting to an optimum BSFC.
Less air needs less fuel = less Hp on the day, but the best power egt remains constant.
Anything that changes the egt ( weather, trapping efficiency due to porting etc ) will change how the pipe reacts - more so than the change itself.

Thanks for sharing. This is good stuff! Feel free to go on another 5 pages because we are TWO THOUSAND in so far.

Are the EGT changes due to weather and engine modifications (trapping efficiency) handled the same?

It's clear the jetting adjustments for the weather at the track, dyno, etc to maintain a tune. However it does bring up a good point about dyno corrections for 2T. The regular atmospheric dyno corrections probably don't account very well for 2T performance differences, assuming you didn't make any jetting corrections. The change in EGT probably causes a much bigger performance change than just the straight up atmospheric correction. I think that's what you are saying if I restated correct.

Also interesting is the radiation prediction for the day. I assume rain or mud on a pipe would add another variable into the prediction equation for the day.

Now onto the changes due to, I'll call it, engine modifications (porting, compression, squish etc.). Let's say you changed compression and/or squish. If you re-jet back to your baseline EGT, couldn't your AFR actually end up different? Changing the squish, for example, effectively changes the burn rate and combustion timing. It seems any timing change, burn rate or ignition, could result in a totally different combustion characteristic to get back to target EGT. At this point would you go back to AFR and ignition timing sweeps to find best power, and record your new target EGT?

Then there is the exhaust... Are there any modifications to the exhaust that you simply re-jet for target EGT and measure power difference instead of doing AFR and ignition timing sweeps to find new best power EGT?

[Frits Overmars]

Pictures attached, but it seems I am not capable of doing the translation.

Never mind Norman, as long as the pictures themselves are in English .
I encountered this engine in the Molenaar GP-team where Hans Spaan tried to bring it on par with the 250 cc works Hondas on which he had been working previously. The Suzuki suffered from a lack of power and an overdose of complexity. Each cylinder had an exhaust power valve with no less than three blades, called SAEC, and an ATAC-type resonance volume, called AETC, which brought a lot of unwelcome heat in the cylinders.
Spaan planned to produce his own cylinders (which would have had all the characteristics of Honda cylinders) but when Suzuki got wind of it, they insisted that the factory would take care of that, if Hans would only provide the drawings. Nothing ever happened, but in any case Suzuki did not lose face quite as much as Yamaha did, when Harald Bartol made them pay him for putting shameless Honda-copies on the Yamaha TZ125 (and on the 125 cc Derbis. And on the 125 cc and 250 cc KTMs).
The best thing of the Suzuki works engines were their pistons, consisting of a light-alloy base material with embedded ceramic fibers. Spaan claimed they lasted ten times as long as Honda pistons.