ESE's works engine tuner

[Frits Overmars]

Extracting 49 gearbox-HP out of the reed valve Derbi was the best Jan could do. I must have the curve somewhere at home, but I am not.
There were several pipe modifications but I don't remember which pipe gave those 49 HP. It's eight years ago...

Is the potential low drive-ability gains from a reed masked by the 9000rpm start because the curves are eerily similar?(other than the flatter peak of the Derbi reed) Granted a GP rider wouldn't use less than 9000rpm.

A GP125-rider spotted below 10,000 rpm ought to be fired.

A more brutal/abrupt power delivery is something i have always noticed when riding Disk valve engines compared with similar power reed valve engines....

Maybe when it comes into the power band. But then that would be your own fault; you should keep it in the power band at all times. And once in the band a disk valve engine's throttle response is much more linear and thus more sympathetic than a reed valver's. If not, you should work on your carburation.

Lastly were you ever able to retrieve the SAE papers that Fleck submitted regarding Water injection?

No, and I didn't bother either. We gathered experience with water injection long before Bob Fleck did, and it taught us that although bottom power becomes a lot better, it doesn't do any good to lap times. So it's no use dragging the extra complication around.

[Frits Overmars]

Wobby (or Frits): how many hours would you expect to get out of big end bearing (thus rod life as well) in a racing engine application?

I can only speak for the Aprilia RSA: its big end bearing is bulletproof. On the test bench it lasts a full season. But on the track it all depends on the rider.
Flashback: when leaded fuel got banned in GP racing, the Aprilias went from a 19.5:1 compression ratio to 14:1. Works riders Harada and Rossi had no problems (on the contrary: the engines became much more flexible) but Capirossi suffered one big end failure after another.
The datalogger revealed the reason: when signor Capirossi came upon a slow corner, he shifted down three times and then grabbed the front brake. In that order. Engine braking they seem to call it. Engine breaking more like...
With the previous 19.5 compression ratio engine braking was such that the revs went up to 15,000 for a moment. But with the 'unleaded' compression ratio Capirossi's engine revved to 17,500. Bye bye big end .

[husaberg]

I can only speak for the Aprilia RSA: its big end bearing is bulletproof. On the test bench it lasts a full season. But on the track it all depends on the rider.
Flashback: when leaded fuel got banned in GP racing, the Aprilias went from a 19.5:1 compression ratio to 14:1. Works riders Harada and Rossi had no problems (on the contrary: the engines became much more flexible) but Capirossi suffered one big end failure after another.
The datalogger revealed the reason: when signor Capirossi came upon a slow corner, he shifted down three times and then grabbed the front brake. In that order. Engine braking they seem to call it. Engine breaking more like...
With the previous 19.5 compression ratio engine braking was such that the revs went up to 15,000 for a moment. But with the 'unleaded' compression ratio Capirossi's engine revved to 17,500. Bye bye big end .

Maintenance schedule for the RSA.

Here.
Let's hear it for Mental Trousers: he created a way for me to upload BIG files.
I will be offline for a couple of days, but this might keep you busy:

http://www.kiwibiker.co.nz/manual/Aprilia-1.zip

One request:
Don't spread the contents all over the world wide web.
Then I might upload some collected data of other racing brands as well.

Enjoy.

Now this is a bucket racer/kart track friendly dyno curve.
This could cut down the changing around mt Welly


I had a look through the RSA125 and RSW125 manuals i was surprised to see the RSA has a much larger o ring on the disk valve cover.120 vs 126mm
Does this mean that the Rotary valve on the RSA is 4-6mm larger in diameter than the RSW or just the o-ring is out further?
I always assumed they were the same size?

interesting ignition overview.http://www.jetav8r.com/Vision/Ignition/CDI.html
modifying a Kawa CDI think its been posted ages ago...http://www.geocities.com/a57ngel/moto/CDI-mod.html

.

This http://www.geocities.com/a57ngel/moto/CDI.html talks about repairing/modifying a KDX CDI's retard curve, there is also a schematic.

Frits Overmars Pitlane
In a 125 cc race engine the spark-plug sparks at about 14° BTDC @ 13000 rpm. Then combustion starts really slow: after the spark another 10° go by before you can detect the first signs of combustion. Then combustion continues for a little over 40° (this is at full throttle; with less cylinder filling, combustion is a lot slower).

Is it useful to slow down combustion on some operating phases? Yes and no. I will try to explain this in a little physics lesson.
No matter which way the piston is moving, as long as there is combustion, the pressure in the cylinder keeps rising. Only after combustion is finished the expansion of the burnt gas can begin.
Slow combustion means that the piston is already well on its way down before expansion can begin; it means less expansion for the burnt gas in the cylinder before the exhaust ports open.
Less expansion means less cooling down of the gas in the cylinder: it is still hotter when it enters the expansion chamber. In hotter gas the speed of sound is higher and that means a higher resonance frequency for the cylinder-pipe system, so it works better at high rpms.

But how do you slow the combustion speed down? Less squish? Mixture too rich? You do not want to do that...
Fortunately there is a simpler solution. We do not slow combustion down; we just start it later: we retard the ignition timing. As far as the exhaust gas temperature in the expansion chamber is concerned, the effect is the same: the engine runs better at high revs.
That is the reason for programmable ignition systems.
Below the power band the ignition advance can be more than 30° so that there is a whole lot of expansion; the burnt gas contains hardly any energy when it enters the exhaust pipe, so the exhaust pulses that arrive at the wrong moments at low rpm, are weak and will not disturb the scavenging too much.
At the rpm of maximum torque the ignition advance is about 14° (careful, a litte too much advance here and you get detonation), and at maximum revs the advance can be 10° or less (Honda even went to 3° after TDC ).

[cotswold]

The beast with it's toned down cylinder finished Taumarunui with engine and rider intact. This was not to say Tee Zee sat on the fence watching his bike go round all weekend though.
It was evident after the very first practice run that the engine was nice and easy to ride but had an issue that would cut our trip short very quickly if not addressed. The engine was suffering from quite severe detonation issues near the end of it's power band and into over rev. TZ played tunes on the carburettor all day on the Saturday, Rob will have to tell what he did but it was extensive. Ultimately we had to go up a couple of teeth on the front sprocket to try and stop the red light telling me all was not well and it enabled me to get the beast into a couple of lonely 7th places.
Race 1: I had a great start and was right with the leaders but the main that was put in before the start was a genuine item and not a knock off and it flowed way more and became impossible to ride and bogged badly on gear changes so I pulled out.
Race 2: 15 laps An uneventful 7th but had to ride to the det sensor which left a fair few rpms still unused
Race 3: 20 laps a carbon copy of race 2.

[TZ350]

Tim did a great job of peddling the bike and giving me feed back so we could get it setup for racing the next day.



While working the dyno by myself it was a bit hard to tell at what rpm detonation was happening, I really need to video the runs so I can play them back and see the red det light and computer screen at the same time.

Anyway as best as I could tell, on the dyno, the deto that was happening was well into the over rev range. So I hoped it would not be a problem on the track.

Just before leaving for Taumarunui I retarded the whole ignition map 2 deg and set the automatic detonation retard to another 4 deg and crossed my fingers.

But as it turned out the bike was topping out down the front straight and flashing the deto light big time. I could see the deto light from the side of the track as Tim went past and on occasions hear the deto too.

So we upped it a few jet sizes, were using after market Keihen style jets and went up in steps from 135 to 160 but was still getting deto in the over rev region.

The next thing was to up the front sprocket to stop it over reving in top, we went up one then two teeth on the front, that didn't work either, I guess Tim was getting faster.

The next move was a smaller air correction jet to richen up the fuelling on over rev, no luck, still got deto on full throttle in the over rev area.

We had changed a lot of main jets and were starting to suspect the new needle was too fat and restricting fuel flow in the main jet range.

Next move was a really big jet, a genuine Keihen 170 and that flooded so bad that every time Tim backed off it was like putting the brake on and Tim sensibly retired from race one so he didn’t get rammed from behind and take someone else down. But it did cure the deto problem.

We fitted a 165 after market jet and that ran ok but still with deto on over rev.

Our thoughts at this point are:-

(1) After market Keihin style jets are not the same as the genuine ones, no surprises there I guess. In fact the only difference between an after market 135 and 165 may just be the number stamped on the side.

(2) B10H plug and an extra 4 deg auto retard on top of the TPS retard map did not cure the deto, so probably not an ignition timing or plug thing.

(3) Deto in over rev, may mean, not enough blowdown time area for those rpm, Frits and Wob talked about that.

(4) I might have to look at some way of automatically dumping pressure out of the expansion chamber when detoing in over rev.

But I do know I am going to buy a range of genuine Keihen main jets as I have lost faith in the after market ones.

[TZ350]

I have shown before you can achieve the power needed to beat 4T 150cc with conventional set up ...

I must have missed that, does anyone else know where to find it???

I would like to see ESE actually put up a fight on the track.

Did I miss something? I would have thought the ESE team and bike achieving 9 wins from 9 starts was a bit more than "actually put up a fight on the track" ...

Thats true, Avalons bike that Chambers prepaired for her with Thomas and Bucketracers help annihilated everything when she took it out, its just a pity she is to busy riding in other classes to have been able to bring her F4 Bike to the recent Bucket meetings.

[TZ350]

The boys got the Kart clubs scales working so, here are some of the F4 bikes at Taumarunui and their weights.



Str8s basicly stock 14rwhp (aprox) FXR150 ... 102kg



Crazymans hot 22 rwhp (I think) FXR150 ... 105kg



Just for Richban, a picture of a Colt Cams sticker. (the Griffiths boys made me do it) ...

Rich's FXR/MC21 is 24rwhp and reputed to be ... 89kg (comment from Rich "Andrews RS is 85/87 I think")



AC Snows fast Honda framed TF125 ... 93kg



Henk and Rick52s sidecar ... 112kg

[TZ350]

Taumarunui 2



Water cooled TF100 CrazyMan 2T ???? rwhp ... 82kg



Kobas MC18 framed MB100 special rwhp??? ... 89kg



FarmerKen's MC18 TF125 rwhp???? but fast ... 85kg



Regans 24 rwhp FXR150 special ... 84kg



Rick52's 21 rwhp RS TF125 special ... 75kg



The Beast 27 rwhp 3LN FZR Suzuki GP125 ... weight ??????

[SS90]

I must have missed that, does anyone else know where to find it???



Thats true, Avalons bike that Chambers prepaired for her with Thomas and Bucketracers help annihilated everything when she took it out, its just a pity she is to busy riding in other classes to have been able to bring her F4 Bike to the recent Bucket meetings.

As I understand it (correct me if I'm wrong) the bike that Avalon was riding was 24HP, with a different pipe and suitable blowdown time.

[TZ350]

North Island Round 3 results from Taumaranui



A Grade.


B Grade


Side Cars

[crazy man]

North Island Round 3 results from Taumaranui



A Grade.


B Grade


Side Cars

thanks for posting this tz ps my bike is around 22 rw hp

[richban]

Just for Richban, a picture of a Colt Cams sticker. (the Griffiths boys made me do it) ...

Rich's FXR/MC21 is 24rwhp and reputed to be ... 83kg

Bless. At Manfield I will be bring some Kelford stickers for them. Mine is 89kg at the mo. Andrews RS is 85/87 I think.

[richban]

As I understand it (correct me if I'm wrong) the bike that Avalon was riding was 24HP, with a different pipe and suitable blowdown time.

More like 26 /27.

Don't forget the rider guys. The rider has quite a lot to do with it.

[SS90]

More like 26 /27.

Don't forget the rider guys. The rider has quite a lot to do with it.

Im not forgetting the rider at all there Rick, just continuing the idea that less is more as far as power goes. I really was certain that the bike Avalon was riding had 24HP, but it goes to show that the race wins for ESE have all come on the shoulders of the lower side of the maximum power, and as a result gained rideabilty.

Am I correct in saying the fast 4T engines have around 24 HP at around 11,000 RPM?

[FastFred]

Its not just about reliable hp and rider and ride-ability of the bike, there is another essential piece to the jigsaw that only TeeZee and more so RMSEng have been talking about.