ESE's works engine tuner

[TZ350]

No. Still dry sump oil dribble over ths gears may be the problem or some incredibly rough down changes. Know more when I get it apart.

[TZ350]

Page 1650 .....

And its been several months since one of my musical interludes, https://m.youtube.com/watch?v=7YDPNl7PeUU

Suzuki used this idea in 1962; they made the third transfer port of their 50 cc works racer as high as the exhaust port, with the intention of pressurizing the crankcase. But in 1963 this third transfer port was no longer any higher than the others...

I think, and always thought, that this was just a mistake made by the draughtsman.
Or a 'joke' from Suzuki, as this is just impossible....maybe to mislead the opposition.....

All 'normal' 2-stroke engines are rev-limited by the blowdown.
When the blowdown becomes insufficient, at high rpm, exhaust gases enter the crankcase.
They usually cause backfiring in the carburettor, sometimes destroying even the inlet valve or reeds.
At Aprilia we could see this very clearly: the transfer passages and crankcase inside became black.

The Ryger, of course, has far insufficient blowdown.
Without it's extremely high crankcase compression it would probably not rev past 10.000rpm.
I really wonder if mixing burned gases with the fresh charge can in any way be positive....
It really can cause auto-ignition of course!
We'll see, the 50cc development will not remain a secret for a long time I suppose!
The spacer under the cylinder looks higher then normal.
Maybe because of a longer connecting rod, which would be good for reliability.....
The people working on it are among the best and most experienced in Holland.
So if they don't make a success of it there really is no hope....

That would be a perfect example of history repeating itself. Suzuki used this idea in 1962; they made the third transfer port of their 50 cc works racer as high as the exhaust port, with the intention of pressurizing the crankcase. But in 1963 this third transfer port was no longer any higher than the others...

Avgas,or any leaded hi octane race gas runs best with hi com and lean mixtures.
Pump gas or no lead gas makes better power when running richer, with less com and generally more advance.
But in some applications ( like KZ2 ) we need to run lean with pump gas to get pipe temp,its a trade off between outright peak Hp and rev ability.
So pump gas " can " use the same TuBmax numbers as Avgas in EngMod, it depends upon the end use and mechanical setup of the engine.

For years Kawasaki used rubber inserts in the clutch cush drives. The 550 to Z750 all used the same setup - which collapses when you get more HP.
I've made up urethane bushes with good results. If you find the stuff you've ordered is too harsh, just make them give a little more with a hole in the center...

The RSA big-end pin was 22mm
On the RSW 21,3 was tried, with one roller more.
It gave slightly less power.
This may have been caused by less crankshaft stiffness or by more friction.
So I don't think 22mm was the best solution....
And the RSW's 20mm never gave trouble!
A 22mm big-end does not guarantee a stiffer crankshaft.
The outside diameter of the crank wheels is just as, or even more, important.
Sorry, I don't remember the RSA crank web diameter.
But I do remember they seriously disturbed inlet flow.
So we had to use a longer connecting rod of 120mm
With hindsight, I consider the RSA a mistake.....
At the time I was too obsessed with the RSW's bad inlet flow, disturbed as it was by the connecting rod...
When the first RSA crankcase arrived at Derbi I immediately did an inlet flow test, of course.
It flowed less than the RSW, I remember feeling VERY disappointed....

How did you measure inlet flow? Flowbench, head off, 3 different transfer openings... then averaged

If you do it this way you would only be measuring transfer flow....

Why did RSA make more power than RSW if inlet flow was down?

There are many more factors in an engine determining power!

Jan could you elaborate a bit on the inlet flow of the RSA.
I know you tested the kart engine with the shields over the wheels, as these have the inlet flow in the opposite direction
to the top of the flywheels - and that made more power when reversed.
But the RSA had the wheels rotating into the case at the top - ie the same direction as the rear inlet flow.
And I would have thought that the rod would have alot less bad effect on the inlet when moving forward and backward, unlike the RSW
where it moved across the flow direction.
Do you think the shape directly after the rotary valve was " wrong " or was something else interfering with the rear inlet flow into the case.

Yes Wobbly, the 'other side' of the cylinder was now like a wall the flow collided with.
Of course many shapes of the duct after the valve should have been tried, but it was not done....
Directing the flow towards the transfer ducts, like in a read valve engine.

My task at Aprilia after I returned from Derbi was cylinder development.
To use a cylinder on the RSA the rear side had to be cut off as much as possible.
As it stood in the way of the inlet flow.
After this cutting such a cylinder gave less power on a RSW and 250
So we did this as least as possible....

And I was not very happy to return to Aprilia, after 1.5 year at Derbi, but had no choice.
So I lost interest, worked very little, and retired the year after.

When I was gone they saw their change to try a 'Honda'-type exhaust duct and port.
They lost 1,5HP, because they had to make the A-ports narrower I think.
What are your thoughts about 'Honda type' vs triple ports?
Have you ever been able to make a honest comparison?
At Derbi I had cylinders with triple ports cast and nikasil plated, they were ready to try when I had to leave....
Still I have some regrets about this.

Det buttons.

https://www.kiwibiker.co.nz/forums/s...post1130263736

https://www.kiwibiker.co.nz/forums/showthread.php/86554-ESE-s-works-engine-tuner?p=1130792235#post1130792235

Attachment 328563Attachment 328564

Avgas,or any leaded hi octane race gas runs best with hi com and lean mixtures.
Pump gas or no lead gas makes better power when running richer, with less com and generally more advance.
But in some applications ( like KZ2 ) we need to run lean with pump gas to get pipe temp,its a trade off between outright peak Hp and rev ability.
So pump gas " can " use the same TuBmax numbers as Avgas in EngMod, it depends upon the end use and mechanical setup of the engine.

Numerical Analysis of a 2T engine with various fuel injection options.

https://www.google.be/url?sa=t&sourc...JoAk0M2iu5-Mdg

I first tried it on a 50 cc in 1074: more power.
Going from 80 to 85
Then at Aprilia in 1996: more power.
Without varying the crankcase volume.
We went from 112 to 113 and 115, later 118 was tried, still better.
For the RSA we had to lengthen the connecting rod from 115 to 120 to improve inlet flow: more power.
It is mainly due to piston friction I think.
NSU already found this in 1953, piston friction was the main source of friction in their 250 4-stroke engine.
It may be different for a reed valve engine, I have not much experience with these.
But the piston friction loss will, of course, be the same in a reed valve engine.

Of course at BDC there is no difference as you have to adjust the cylinder height!
Maybe it is interesting that with a longer connecting rod I could use higher transfer ports on my 50.
Getting still more power!

The crankcase volume also changes, of course, unless you change the position of the piston pin in the piston, as we did at Aprilia
This can be better or worse....
You can change your crankcase volume in many ways.
But always keep in mind that flow is more important than volume.....
On rotary valve engines I found the bigger the better, within reason of course....
The Aprilia engines had very narrow crank wheels, (16mm) so a very big crankcase volume. About 660cc in TDC
A big crankcase volume makes very long inlet timings necessary.
And big carburetors.

This is probably the reason why reed-valve engines need a smaller crankcase volume.
The reeds 'decide' for themselves when to open...
They need some depression.
And because maximum inlet flow is probably determined by the reed block, big carburetors won't work on a reed-valve engine.
They just slow down the flow in the carburetor, making for a difficult carburetor adjustment.

So I think that a rotary valve engine will always give about 3-4 HP more (125cc) than a reed valve engine.
Because of its unrestricted inlet flow and less pumping losses.

Oko Powerjet nozzle too short? Doesn't seem to flow much at all on my bike...

Powerjets were originally developed for piston port induction, with the nozzle feeding in from the top of the carb bore, the idea being that at part throttle there would be no airflow across the nozzle, so no fuel flow through it. The powerjet would only come into action at full, or allmost full throttle.
Today, powerjets are used in a different way and the top-feed position has no advantages any more, while it still has the disadvantage of a slow reaction due to the long path from float bowl to nozzle exit, plus the fact that the fuel first has to be sucked all the way up to where the hose connects to the nozzle. As long as there is not enough suction to pull the fuel 'over the hill', nothing will happen at all.
If you position the nozzle lower, like on the picture below, response will be a lot better. Make sure that you view the picture in its full format; klick on it 3 times.
Attachment 328240

With your Fabrication skills I'm sure you could duplicate most of the components.

http://www.pingelonline.com/air-shif...ar-control.asp

[husaberg]

No. Still dry sum oil dribble over ths gears may be the problem or some incredibly rough down changes. Know more when I get it apart.

what was the oil feed rate in ml\s minute, i remember you were going to use an autolube pump i would expect they would be very low flow rate.

[Grumph]

No. Still dry sum oil dribble over ths gears may be the problem or some incredibly rough down changes. Know more when I get it apart.

If there's a gear running on a bush on the shaft, you will need an internal feed too...Found this with GSXR boxes, the bush for 3rd in the middle of the 6 speed 750 box was the weak spot. Up the feed to it and you could put the 750 box in an 1100.
But of course it's an old box too....

[TZ350]

what was the oil feed rate in ml\s minute, i remember you were going to use an autolube pump i would expect they would be very low flow rate.

Finding a suitable gearbox oil pump has been a bit of a mission. Tried quite a selection of pumps, they all failed at some point or other. There have been vacuum diaphragm pumps, electric centrifugal pumps and plunger pumps. 12V garden feature water pumps, pressure diaphragms and fuel pumps. Mostly 1-3 l/min, 5 l/min seems ideal, inexpensive with low current draw is a must.

My favorite was a Toyota windscreen washer pump, took 3 amps and delivered a good jet of oil but over heated after a few minutes and stopped but would always restart after a rest, protected by an internal thermal overload switch I guess.



Not sure yet if the gearbox implosion is a lack of oil problem or the really really rough downshifts on the dyno when the motor cut out, probably both. Performing a gear box autopsy soon.

I have a couple of these coming. they look like they are meant for continuous operation. Their intended use is to supply water to concrete cutters. Current demand, flow and pressure all look good. Looks like a slightly bigger version of the Toyota windscreen wiper pump.

• Adapter Output voltage: 12V 3A
• Water pump voltage: 12V
• Power: 30W
• Adapter plug: US plug
• Lift: Approx. 6 meter / 19.7ft
• Flowrate: 6L/M
• Water inlet: Approx. 16mm
• Water outlet: Approx. 6mm
• Water pump size(HxD.): Approx. 88mm x 32mm / 3.46inch x 1.3inch
• Working temperature: 0-80℃

[Grumph]

Have a look at the little Honda 4T single oil pump - CB100 upwards. Narrow gerotor pump which could be driven by an oldham coupling or similar off the end of a gearbox shaft. Heaps of them around too. Minimal power loss I'd think.

[husaberg]

Have a look at the little Honda 4T single oil pump - CB100 upwards. Narrow gerotor pump which could be driven by an oldham coupling or similar off the end of a gearbox shaft. Heaps of them around too. Minimal power loss I'd think.

The CRF50 and its many derivatives has a natty little gear pump with a tab drive that could easily be driven on the unused kickstart gear and idler setup.


On another topic the plenum
Kawasaki Disc valve engines had these

[Grumph]

That CRF50 pump looks like the gerotor setup from the CB singles in a different body. Probably is too, if something works, Honda seldom change it....

[husaberg]

That CRF50 pump looks like the gerotor setup from the CB singles in a different body. Probably is too, if something works, Honda seldom change it....

Its def a smaller housing, smaller gears likely, narrower too i think. i could compare them i have one of each somewhere, i have a high output takakawa crf50 one, Rob is welcome to it if he wants it.
The Pitbike ones i think have plastic drive gears likely recycled wok internal gears as well.
hers is an inside pic crf70

[Frits Overmars]

I remember Jan saying he would do a dual disc (one either side)
Is it fair to say the RSA breathing improvements with its rear disc did not meet the Jan’s initial expectations for the expected improvement over the single side disc?
Also I recall something about the RSA250 rotation direction being reversed, compared to the RSV250. what were the reasons this was done?

Yes, Jan would do a dual disc now.
Is it fair to say...? Well, yes and no. The RSA was an improvement over the side-disc RSW alright, but not by as much as Jan had hoped for.
But as the RSA was winning GPs, Aprilia-management decided not to spend any time and money on development; there may have been a few more horses in there, waiting to be unleashed.
You're right about the RSA250's rotation direction being reversed, compared to the RSW250. The various shafts in the engine were moved about in order to make it more compact. In the RSW the top crankshaft was driving the clutch; in the RSA it was the bottom crankshaft.
Left to right: RSW250, RSA250, RSA250.

[Frits Overmars]

Exactweld did a dual disc, Puch did a disc/reed combination. Has anyone other than Helmut Fath used same side, contra-rotating discs?

I'm not aware of anyone else doing contra-rotating discs. But I do know that the Puch works bike had no disc/reed but a disc/pistonport combination;
I took the engine apart the same year that Harry Everts rode it to a 250 cc MX world title.

[husaberg]

Yes, Jan would do a dual disc now.
Is it fair to say...? Well, yes and no. The RSA was an improvement over the side-disc RSW alright, but not by as much as Jan had hoped for.
But as the RSA was winning GPs, Aprilia-management decided not to spend any time and money on development; there may have been a few more horses in there, waiting to be unleashed.
You're right about the RSA250's rotation direction being reversed, compared to the RSW250. The various shafts in the engine were moved about about in order to make it more compact. In the RSW the top crankshaft was driving the clutch; in the RSA it was the bottom crankshaft.
Left to right: RSW250, RSA250, RSA250.

Thanks Frits
Did the riders report any difference in steering characteristics or were possible effects masked by differing weight distribution anyway.
Or was the compactness more to do with engine width?

[bucketracer]

Those gear pumps look the business, unfortunately I think TZ had to cut the starter gear off the back of the clutch so he could fit that big KE175 rotary valve. The starter gear also drove the Posilube pump otherwise he could put one of these where the original Posilube oil pump was. Maybe he could drive one directly off the outer end of the gearbox input shaft.

[husaberg]

Those gear pumps look the business, unfortunately I think TZ had to cut the starter gear off the back of the clutch so he could fit that big KE175 rotary valve. The starter gear also drove the Posilube pump otherwise he could put one of these where the original Posilube oil pump was. Maybe he could drive one directly off the outer end of the gearbox input shaft.

I'll have a dig in the shed and send Rob one, I think i have a CB100 on as well.

[Frits Overmars]

Thanks Frits. Did the riders report any difference in steering characteristics or were possible effects masked by differing weight distribution anyway. Or was the compactness more to do with engine width?

Feedback from the teams to the racing department was severely discouraged by the technical director; must have been a case of 'divide and conquer'.
And Jan Thiel did not concern himself with the cycle parts at Aprilia anyway, so I cannot quote on any rider reports.
As far as I know the main reason for the layout change was to alter the position of the gearbox output shaft.