ESE's works engine tuner

[peewee]

No husaberg the old RS125 one is very short and dead straight.
The KTM does reduce the asymmetric flow within in the reedblock, but then that reduced asymmetry is made alot worse by having
the flow exiting the reed tips made to run off to one side of the cylinder/case,no matter what is happening within the reed.
This will mean that no matter how clever the reed tensions are made to equalise the flow exiting the tips,the flow into the transfer duct entries
above the crank will always be asymmetric.
Not so clever at all IMHO.
As I said in a CR125 or a RS125 having the dead straight manifold is worth a couple of HP, as the flow is dead straight horizontally as well as vertically.
In the KTM that is actually impossible.

straight inlet and kinked manifold or rotated inlet and slightly less kinked manifold. either way you look at it i guess youll have more mixture piling up on one side of the inlet as it tries to turn the corner.

well i got started cutting the aux. everyone talks about the axial angle on A,B and C but never any mention of the axial for the roof and floor of the aux. got any suggestions ? tried to look at the rsa but couldnt really tell much from the odd angle photos ive seen

[husaberg]

straight inlet and kinked manifold or rotated inlet and slightly less kinked manifold. either way you look at it i guess youll have more mixture piling up on one side of the inlet as it tries to turn the corner.

well i got started cutting the aux. everyone talks about the axial angle on A,B and C but never any mention of the axial for the roof and floor of the aux. got any suggestions ? tried to look at the rsa but couldnt really tell much from the odd angle photos ive seen

Have a look in the Rsw Drawings........

[peewee]

yes i should of thought of that. it appears the floors angle down immediatly from the bore edge. the roof however looks to be flat for a few mm into the duct and then angle downward. do you agree ?

[husaberg]

yes i should of thought of that. it appears the floors angle down immediatly from the bore edge. the roof however looks to be flat for a few mm into the duct and then angle downward. do you agree ?

that tallies with the DEA cylinder I have seen
plus this cad rendering of the RSW one
http://www.kiwibiker.co.nz/forums/al...hmentid=301360
Mr Payart has posted quite a few pics on his pitlane thread inc 3d pics

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
http://www.kiwibiker.co.nz/manual/Aprilia-2.zip
http://www.kiwibiker.co.nz/manual/Aprilia-3.zip
http://www.kiwibiker.co.nz/manual/Aprilia-4.zip
http://www.kiwibiker.co.nz/manual/Aprilia-5.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.

[peewee]

i think what ill do is just make the port as big as need be. then weld a bubble over the outside so theres still water circulation

[F5 Dave]

And then test it for leaks. Water inlet in the back - nice. Is that a later CPI like a Wampus or something?

[husaberg]

Other pics

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[TZ350]

Pumper

With a pumper carb this engine reliably made 28hp at 12,250 rpm, with EFI, 24hp at 11,500rpm is the best so far and the EFI is short about 1,000 rpm.

EFI

Fuel pump packed up so gave up for the night. Ok this is where I am at, pretty much the same position as 6 months ago. Still detos like crazy especially on over run so I will try Drews idea and run a 3D ignition map that backs out a lot of ignition particularly on part throttle. And play a little with the injection end point. I will give it a few nights then try the direct injection down the inlet idea.

[speedpro]

I thought the problem was "auto" ignition caused by the mixture in the transfer ducts being heated by a burst of hot exhaust gas overcoming the weak pressure in the case/duct momentarily before it finally makes it's way into the cylinder where it is polluted by burnt hot gases before being compressed at which point it autoignites. Supposedly more of a problem with methanol as methanol is more prone to autoignition when mixed with combustion products.
If that is the case, if, pissing with timing is not going to make any difference as it is not a regular ignition event causing the problem. Playing with the mixture may help but will cause problems with pipe temp affecting throttle response.

maybe.

[Martin1981]

or you could do what ktm did, although it may be alot of work

both cylinders have the same total angle of 20*. the honda on the left has the full 20* in the manifold which makes a kink so to speak. ktm on the right has 10* angle in the cylinder inlet and the other 10* in the manifold. who ever said them guys at ktm were a bunch of rubes

that`s what i was think of peewee. but like wob said. even having this work done you still have a bend. so i will go for dead straight probably. the only thing i need then is a trick shit rubber boot to connect the carb to the airbox.

[husaberg]

Yep, thats the trick shit part for the last of the MX based RS125s - NLA,except a few lying around that were used in open class CR125 engines before they stopped them in USA.
Thats worth a couple of Hp and then stick on a short PWM or better SPJ and thats another 1 1/2 at the top ( over PWK ) in the MX or early RS125.

When you run out of those have a look at these big enough base plate to be modified to fit any number of bikes only 35mm carb though

[TZ350]

I thought the problem was "auto" ignition caused by the mixture in the transfer ducts being heated by a burst of hot exhaust gas overcoming the weak pressure in the case/duct momentarily before it finally makes it's way into the cylinder where it is polluted by burnt hot gases before being compressed at which point it autoignites.

Detonation was not a problem with the carb and 3D ignition map until well past 12K rpm.

But .. Yes Auto ignition and I think you are right about the EFI creating a weak mixture in the transfers so I intend putting in some effort to get the timing of the injection squirt to coincide properly with the transfer port open time.

When I shut the EFI beast off at 9-11.5K rpm the deto sounds like a swarm of very angry bees.

[41juergen]

Hi everybody, my name is Juergen, I'm from Frankfurt (Rhein-Main Area) in Germany.
I found this fantastic thread some month ago and it took me some time to get through it. Of course it's the most valuable source in the net, thanks’ to TZ, Wob, Frits and all the others sharing your knowledge. As per good advice I got the EngMod software paid by my wife (with the basic idea better to simu some pistons to dead rather than buying new ones... ).

So I use a RZ PV engine with a 66x58mm setup, STA's to reach approx. 50 HP per cylinder, a 0,8mm squish with 48% SAR, 38mm Mikunis, a zeeltronic and a "tuned" pipe setup. Now playing with the numbers some questions raised up:
- for the scavenging model I use Yam1 for the modified ports setup. Is that ok?
- is a combustion efficiency value of 0,9 too high for that setup? I get detos at approx. 8000 rpm by using 100 octane fuel and can get rid only by going down with AFR to 11.2...
- is a TL for the pipe of 950mm too long for max. power at 10500 rpm and 130 tr and 200 ex timing? The power / torque curve shape looks not too bad with having max power at 11.000 rpm but than going down fast (even with playing with the ignition and AFR)...

Thanks’ for any help...
Juergen

[Muciek]

Detonation was not a problem with the carb and 3D ignition map until well past 12K rpm.

But .. Yes Auto ignition and I think you are right about the EFI creating a weak mixture in the transfers so I intend putting in some effort to get the timing of the injection squirt to coincide properly with the transfer port open time.

When I shut the EFI beast off at 9-11.5K rpm the deto sounds like a swarm of very angry bees.

Here are BRC EFI 125 engine videos





And photos of power curve and inlet


Using ball valve slide injectors can be in front of it or they should be behind it?

[TZ350]

Two injectors in the inlet, guess where we are going shortly, thanks for the pictures.