Ignition curve for 600cc?

[sehlis]

Hi!

I'm new to this forum but have my Gilera since 2001.

Like some of you I changed the ignition cdi to an Ignitech (http://www.ignitech.cz) because of broken standard box.
I have installed it and the bike start perfect. Before I drive the bike I need to type in the right ignition curve in the software. My question is if anyone know what ignition curves it was in standard system so I can type it in for every 1000rpm up to 8000.

The model who works ok can be Piuma, Saturno, Nordwest or Rc600.

I will go for a dyno test later when time is there.

Best Regards
/Christer

[Joachim]

Interesting thing
Did you have a inductive one or a capacitive?
Ignitech will usually send you something which is ready for plug in.
At least they did this for me
But.....
For my inductive they programmed a curve from a Yamaha.
To much delay i thought and used the normal Gilera curve instead.

Delay at start: 7 deg
going up to 30 deg at 4000 revs
cut off ??? I'm just using 7250 or 7500 revs i think.
BTW that's from the manual

That's what i am using. My Nordie is running with that.
I hope to 'play'around a little bit with that, but didnt found the time.
So if you like to share your experienc

ciao joachim

[CB]

Hi
I made some measurements on the ignition curve for the Saturno and a 600 RCR The Saturno is like this:
0-1500: 7 deg. BTDC
2000: 10 deg BTDC
2500: 16 deg. BTDC
3000: 24 deg. BTDC
3500: 30 deg. BTDC
4000: 35 deg. BTDC
4500-8000: 38 deg. BTDC

The 600 is very much the same and differences may be due to tolerances in measurements. Therfore fewer measuring points.
0-1500 7 deg. BTDC
3000: 20 deg. BTDC
4000: 32 deg. BTDC
4500-8000: 36 deg. BTDC

This is of course without any kind of guarantee but will hopefully help you getting started.
The book (or an article i once read) states 7 deg. at idle and then an advance of 30 deg. This gives a total of 37 deg. so my measurements are pretty close.

Summer greetings to you all.
Christian

[Joachim]

Thanks a lot. Saves some work for me
I think i should have a look at the manual again.
Maybe Luigi didn't wrote 'up to 30 deg' but 30 deg *more*

BTW did anybody know when the rev limiter will cut in?
8000 seems to be something to high

ciao joachim

[CB]

Hi Joachim and Christer

Before I made this test I was also much in doubt whether the stated 30 degrees was the total advance of the system or it was the actual ignition point.

Using 30 degrees at full advance is too little and will result in lower power and too much heat (using standard cams, compression ratio etc.) in my opinion.

I don't remember when the rev limiter cuts in, but I'm pretty shure that you can safely rev it to at least 8000 with the very short stroke of this engine. But normally there is no power gain in going that high with an unmodified engine.

/Christian

[sehlis]

Thank's for this info!

I will type in the measurement from the Saturno. Hopefully this works god to start from.

I can tell that my engine is little modified

Today the spec is:
Bore 105mm
Stroke 74mm
Cams from Megacycle
Intake valve 39mm
Exhaust valve 33mm
Carburetor 2x36mm
New exhaust system

The spare engine is the same except the bore who is 103mm.

I will come back with info regarding Ignitech when I have tried the bike.

[sehlis]

Christian,

I forget to ask if your ignition value is whit or whitout base advance?
My base advance is 20° (have a modified flywheel).

I have typed in your value except base advance which I think must be right.

Ciao
/Christer

[kano nordi]

Hi Christer,
Sorry to hijack the thread, but I am interested in your engine spec with 103mm and 105mm bores where did you get the pistons, is it bored out? or are over sized liners fitted, what 36mm carbs are fitted, are the Megacycle cams available.
I am on the lookout for anybody having tuning parts for sale
John

[CB]

Hi Christer

I don't really know what you mean by base advance. All figures are crank shaft degrees starting at 7 degrees before top dead center from 0 to 1500. The electronic then make an advance of 31 degree which you shall add to get to the 38 at 4500.

If you use 20 degree at idle you of coures only add 18 degrees to get to the desired 38. You must then find your own points and program your system accordingly.

Bore of 105? I would also like to hear some more details like piston, head gasket etc.

My engine is with a Giraldoni 102 bore kit. modified head, different cams, 41mm Keihin but still using the standard ignition system.

/Christian

[Joachim]

I don't really know what you mean by base advance.

I think he's meaning where the pickup is mechanically mounted.
At standard Gileras the pickup is at 7 deg before TDC. At least that's what i have measured in a raw way
The ignition should know that the signal did not appear at TDC but somehow earlier.
To send the spark at 7deg BTDC it will ahve to wait another 13 deg.
That was one of the things i would like to ask the guys at Ignitec

My engine is with a Giraldoni 102 bore kit.

Isn't that Gilardoni???

Joachim

[sehlis]

Here is a description of "base advance",

            What is “Base advance“?
We demonstrate it for mostly used one lobe rotor and one pick up. Ignition after start and by low revolution to first rpm point in advance map spark in the time when pick up is at the end of lobe. Advance in this time is base advance.
It is not possible to change “base advance” by software. It is determined by position of rotor and pickup in certain bike. Base advance is usually about 10 degree (from 3 to 22 degree).
This value has to be set to ignition by PC softare. When base advance is properly set, than advance in advance map agree with real advance made by ignition.
Rotating speed is changing in low revolution very much. Sparking at “end of Lobe” make advance stabile. It is mostly convenient to use it also by idle revolution.

So if you mean 38° in total, I need to change my value in software.

Regarding the engine, it's used in my Piuma and competing in Supermono in Scandinavia.
The engine is 20 years old now but still performing good enough to win races!

I'm using piston from Wahl in Germany. For the 105mm cylinder we made a new liners. The 103mm is bored from standard.
On the top of the liners we have made a small edge who is 0,4mm higher. That edge press harder to the aluminium gasket and all problem is gone
Cylinder head is of course modified for a better flow.
The carbs is two Keihin cr36
Flywheel is made of aluminium.
I have 2 exhaust systems. 1 on each side. It's easier to decrease the sound.

I don't think Megacycle cams are available. Mine is over 10 years old.

The last dyno drive showed 75hp (on the wheel) at 8500rpm.
I know there is a difference between the Dynojet on the market. But around that can we expect.
Now we have a better ignition system with the possibility to play around with different curves. I don't know what that can make in terms of horsepower and torque?

[kano nordi]

Here is a description of "base advance",

            What is “Base advance“?
We demonstrate it for mostly used one lobe rotor and one pick up. Ignition after start and by low revolution to first rpm point in advance map spark in the time when pick up is at the end of lobe. Advance in this time is base advance.
It is not possible to change “base advance” by software. It is determined by position of rotor and pickup in certain bike. Base advance is usually about 10 degree (from 3 to 22 degree).
This value has to be set to ignition by PC softare. When base advance is properly set, than advance in advance map agree with real advance made by ignition.
Rotating speed is changing in low revolution very much. Sparking at “end of Lobe” make advance stabile. It is mostly convenient to use it also by idle revolution.

So if you mean 38° in total, I need to change my value in software.

Regarding the engine, it's used in my Piuma and competing in Supermono in Scandinavia.
The engine is 20 years old now but still performing good enough to win races!

I'm using piston from Wahl in Germany. For the 105mm cylinder we made a new liners. The 103mm is bored from standard.
On the top of the liners we have made a small edge who is 0,4mm higher. That edge press harder to the aluminium gasket and all problem is gone
Cylinder head is of course modified for a better flow.
The carbs is two Keihin cr36
Flywheel is made of aluminium.
I have 2 exhaust systems. 1 on each side. It's easier to decrease the sound.

I don't think Megacycle cams are available. Mine is over 10 years old.

The last dyno drive showed 75hp (on the wheel) at 8500rpm.
I know there is a difference between the Dynojet on the market. But around that can we expect.
Now we have a better ignition system with the possibility to play around with different curves. I don't know what that can make in terms of horsepower and torque?

Hi Christer,
That sounds like a very mean machine, with a lot of development put in by you, all credit to you, what is the next step, bigger again?
I looked on megacycle website they do list Gilera cams but no reference to which model.
Regards
John

[kano nordi]

Hi Christer,
I sent you a PM asking for information about your 103mm and 105mm cylinder bores, please advice me did you bore out the cylinders and fit cast iron liners or is it possible there is enough metal to bore the cylinder and get it replated?
Regards
John

[Joachim]

I'm using piston from Wahl in Germany. For the 105mm cylinder we made a new liners. The 103mm is bored from standard.
On the top of the liners we have made a small edge who is 0,4mm higher. That edge press harder to the aluminium gasket and all problem is gone

Joachim

[kano nordi]

I'm using piston from Wahl in Germany. For the 105mm cylinder we made a new liners. The 103mm is bored from standard.
On the top of the liners we have made a small edge who is 0,4mm higher. That edge press harder to the aluminium gasket and all problem is gone

Joachim

Hi Joachim,
I'm surprised there is enough metal thickness to bore out 5mm to 103mm and when fitting a 105mm liner I would like to know how was it sealed.
I'm hopping Christer can give a little more information.
Regards
John