ESE's works engine tuner

[Frits Overmars]

I never worked with the Kawa KMX125 you showed, but the twin cylinder 250 cc KR1S (lovely bike) had the same arrangment. A friend of mine raced one of those in a Dutch stock class against a fleet of 400 cc four cylinder fourstrokes. Being a stock class, there was not much we were allowed to modify in the little Kawa.
Fitting Yamaha TZ250G pistons (lighter, stronger, cheaper(!) and with 1 instead of 2 rings and 1 mm shorter from pin centre to top edge), raising the centre exhaust to the same height as the auxiliaries and milling the cylinder head made it faster than all the foulstrokes.
In the Aprilia cylinders (I assume you are talking about the racers; not the RS250 street bike with Suzuki engine) the blades (there are two of them, one on top of the other) only control the main exhaust port.
In the Aprilia racers there is always a route for air to get out of the cooling system. The coolant flow comes from the crankcase, enters the cylinder under the exhaust duct and exits via the head. In the bottom cylinder of the 250 cc V-twins the air can take the opposite route if need be. The RSA125 has a dedicated air bleed line at the back of the head (see pic).

I did not miss your question regarding the retarding of the disk valves, but I did'n answer it because A: it was not quite clear what you meant; B: it is one of those simple questions where the answer is not simple, and C: I could not spare the time to formulate a civilized reaction to your Bell-quote. Referring to it as Bell-shit as I have done in the past, would not be acceptible in a decent forum like this.

Let me summarize it like this: you can improve the power band by closing the disk early at low revs. But then you should also open it earlier because the transfer phase will be finished earlier at those revs and the rising piston will suck charge back from the cylinder to the crankcase if you do not open the disk as soon as crankcase pressure threatens to drop below atmospheric. So the best solution would be to rotate the whole disk. But what that has to do with reversing the rotation of the rear-driven RSA disk, or any other disk for that matter, is beyond me.

[husaberg]

I did not miss your question regarding the retarding of the disk valves, but I did'n answer it because A: it was not quite clear what you meant;, B: it is one of those simple questions where the answer is not simple, and C: I could not spare the time to formulate a civilized reaction to your Bell-quote. Referring to it as Bell-shit as I have done in the past, would not be acceptible in a decent forum like this.

Let me summarize it like this: you can improve the power band by closing the disk early at low revs. But then you should also open it earlier because the transfer phase will be finished earlier at those revs and the rising piston will suck charge back from the cylinder to the crankcase if you do not open the disk as soon as crankcase power threatens to drop below atmospheric. So the best solution would be to rotate the whole disk. But what that has to do with reversing the rotation of the rear-driven RSA disk, or any other disk for that matter, is beyond me.

Think of a centrifical advance on an old car or brit bike and quite a few old Japas they have a bob weight to advance the timming with speed

the amount of advance can be controlled by both the strength of the springs and the weight of the bob weights.
If this were added to a disk valve engine . As the whole disk would seemingly need to retard with speed on a disk valve engine.
The rotation of the valve would therefor have to be reversed?
I hope that makes a little more sense?
Or is the Bell curves for the disk timing variations fundamentally wrong?

[dmcca]

Just brought one now. thanks.

So did you get one with the analogue output? If so which option best suits the ignitech?

[Frits Overmars]

Think of a centrifical advance on an old car or brit bike and quite a few old Japas they have a bob weight to advance the timming with speed

the amount of advance can be controlled by both the strength of the springs and the weight of the bob weights.
If this were added to a disk valve engine . As the whole disk would seemingly need to retard with speed on a disk valve engine.
The rotation of the valve would therefor have to be reversed? I hope that makes a little more sense?

Not at all, Husa. How about keeping the direction of valve rotation intact (changing it in the RSA125 would be quite complicated) and mirroring the bob weight arrangement?
Centrifugal disk adjustment has been built before; the idea is not bad (I feel you might need a little comfort ).

[teriks]

The future could be another triple port cylinder with the std GP exhaust port width or a purpose made sleeve or better yet, cylinder.

On the sleeved air-cooled part..
What if you'd cut the cylinder just above the export, and make an aluminum liner with a few cooling fins on the top part of the bore? -Should improve cooling somewhat.
(Man this Swenglish aint easy.. did that make sense at all?
Will try harder to find a picture somewhere..)
It' not a revolutionary idea at all, there has at least been a few model engines using such a design.

EDIT: Found something that at least give a hint of what I'm trying to describe:
Source: http://lerner-modellbau.com/product_...27&language=en
Source: http://www.rc-network.de/forum/showt...nnen-in-Melnik
Source: http://fiorimet.home.xs4all.nl/history.htm
You can also see the high temperature O-ring application I mentioned earlier.

[wobbly]

As I said before the knockgauge that works with the Ignitech has an analogue output to ground.
When it detects deto it grounds an Ignitech input that is programmed to retard.
You can watch the lights and then manually take out timing to stop the deto, but the retard circuit of the knockgauge/Ignitech pulls out the timing
so quickly you may well miss this indication.
So I disable the retard initially to see where the advance curve needs to be changed, then reconnect it.
In this case the gauge is a failsafe.

See the pic above of the RSA - the Bosch deto sensor with 8mm hole is bolted to a head stud - that Thiel character was /is no idiot.

[Yow Ling]

Bosch Vibration sensors

http://www.bosch.com.au/content/language1/html/4563.htm

Wobbly , what is the difference between 2 pole and 3 pole types?

Are these available anywhere local, I rang a Bosch distributor in Auck, I think they were giving me the 1000 yard stare on the phone

[Leed]

sorry just read an older posting and had a wee laugh...

"Torque is something you distill from power with the help of a gearbox"



Power is the application of Torque (force) in a timeframe... so a gearbox simply reduces or magnitfies the force (torque)... Power is quanitified by Torque and Time
Power is a product not a factor... primary school

[wobbly]

The 3 pole ones have 3 wires so dont know how these would be connected.
Most are 2 wire and are common to most late model cars, Audi, VW ,BMW, Subi etc, the plug is standard injector type.
Easiest is the one with 8mm hole thru the middle, they are rugged as hell, so rarely bust, whip down to wrecker and get one for jack shit with the plug connected.

[mike schmidt]

We are working on a 175 cc twin (48 x 48) outboard. (Rossi) The performance is not up to where it was when tested in Italy. Is there a diffrence between a 48 mm bore piston and a 54 or 56 mm bore piston in how lean you can go based on plug color? The plugs looked perfect for a 125 or a 250 twin, but I am now thinking you may be able to lean the small bore motor down further.

Any coments?

Thanks

Mike Schmidt

[Frits Overmars]

sorry just read an older posting and had a wee laugh... "Torque is something you distill from power with the help of a gearbox"

I could have written that. In fact, I think I did .

Power is the application of Torque (force) in a timeframe... so a gearbox simply reduces or magnitfies the force (torque)... Power is quanitified by Torque and Time. Power is a product not a factor... primary school

Primary school or kindergarten? Power can be defined as torque*radians per second. Where did you hide the radians?
A more general definition is: power = force*distance per unit time. In short: power=force*velocity. Did you notice there is no torque at all in this definition?

[wobbly]

I dont know if Rossi's dyno reads high but no one else seems to get the numbers as done in Italy.
Plug colour would not change at all from a 54 down to a 48 bore, but maybe it is possible to run a little hotter on egt.
What are the cht and egt numbers - I recommend reading the egt at the end of the slider, where the pipe begins ,not up at the flange,as with so much overfueling going
on with Methanol the gauge will not read correctly.
You would have to be very careful leaning down as they then deto badly off the turns - I hear Rossi is now using a solenoid powerjet carb to try and fix this.

[mike schmidt]

Wobly: Thanks. Deep down inside I knew the answer, but was hoping....

We are grasping at straws on the 175 twin. It ran 10+ mph faster in Italy on a bigger boat. There are some very smart guys helping on this one and everyone is confused. Sereal years ago I invested a bunch of $$ in a duel EGT set up that records. I spent even more $$ on pistons that season. With the amount of methanol we dump into these things EGT is tricky at best. The 175 is running 140 F- 150 F CHT. The plugs are something I would consider dead on in our 250.

The owner went all through the fuel system, electrical system, the top end and obtained a known good set of 175 twin pipes. We are putting my older son in it, as he is is very good at giving feed back.

Note: Last year I built a set of cylinders for Rossi to test. Had some good ideas that I really thought would help his cylinders. Lost several H.P. on his dyno. I just came up from the shop where I am fixing them so they look (and hopefully work) like the Aprilla they were copied from. I sure wish that you and Fritz had shared this information a couple of years ago.

Thanks

Mike Schmidt

[marsheng]

WTF ….. The Beast screams around the track on full song for a whole lot of laps then quits when taken out for an easy trot around in the two warm up laps for the next race, what is that all about?????

Is it possible that before you went on the trot, you topped up the gas and forgot about the oil ???

[husaberg]

Not at all, Husa. How about keeping the direction of valve rotation intact (changing it in the RSA125 would be quite complicated) and mirroring the bob weight arrangement?
Centrifugal disk adjustment has been built before; the idea is not bad (I feel you might need a little comfort ).

Thanks for the hug we all need a hug at times esp my signiture pic, but Frits I am afraid my Italian is worse than woefully non existent (ie its all... er Greek to me)
So to save me the pain of Translate via boobblefish or similar from the text.Did it work ok with any useful gains.I must say even with searches i have never came across anything remotely similar.
oh yeah mirrored bobweights cunning. Also was the curves (Bell) remotely close to what would actually happen?
but i guess no love on the inverted dykes rings for pipe sealing. I did think that would appeal to a Dutchman