Elektronik Sachse pre set ignition curves.

Elektronik saches advance curves what’s your opinions?

I don't really have an opinion, but I did some work on other advance curves. It's here: https://www.accessnorton.com/NortonCommando/electronic-ignition-advance-curves.21964/.

In the first post, the blue curve - whatever ignition that is, is the one you want for a stock bike, None of the other curves reach max advance early enough for best results from a stock engine. The OEM points/AAU advance curve - all in by 3k RPM - is superior. The other curves shown will give away power until the 5k rpm range. IOW, on two identical machines if you rolled on the throttle on from, say, 2000 RPM, the bike with the OEM curve (like the blue curve) would pull away. Of course, if you had both bikes side by side at 5k RPM and rolled on, they would stay even. But why give away some mid range? That's where the most important power is anyway for normal riding.

Interestingly, the curve for the TriSpark in the second post does not match what my Trispark does. Per the strobe, the advance on my TS maxes out at around 3200 RPM, which is the reason I purchased it when I decided to go to E-ignition in '08. It more closely followed the OEM curve than did other E-ignitions I considered.

None of the curves have any idle stabilisation by adding some advance below 1000 rpm which I find useful as long as it also retards down near kicking/starter motor revs. Plus as noted by MM they do all take some time to go fully advanced, good for engines prone to pinking but that is not a problem Norton twins have, would work better on a Triumph.

kommando said:

None of the curves have any idle stabilisation by adding some advance below 1000 rpm which I find useful as long as it also retards down near kicking/starter motor revs. Plus as noted by MM they do all take some time to go fully advanced, good for engines prone to pinking but that is not a problem Norton twins have, would work better on a Triumph.

Click to expand...

I think the graph is misleading, I have been trying to find an installation guide for a norton but can only find a PDF for a Ducati bevel in this it shows the same graph as above
But states advance starts at 400 RPM and depending on curve chosen is between 2° and 8° advance,
Although the graph shows no advance until 1000 rpm
Cheers

This is the curve set for a trispark. The ones above are all preset and can be enabled by selection on the ignitions box. I discounted all that were out with the 31 and 28 degree full advance. I’ve tried a few and the bike runs ok on them all. The motor has a combat head and PW3 cam.
The bike is easy to start .

The optimum advance curve is probably a function of the rod length, the stroke and the revs. The combustion event is probably fixed time for any given comp. ratio, however the rock-over time decreases as the revs rise, so ignition needs to start earlier to maintain the maximum thrust on the piston at the same point, at all rev levels. Compensating for differences in comp. ratio and fuels should probably be done by changing the static advance, thus moving the whole curve. The rest is jetting.
From what I have read, the advance curves currently being used seem to be guess-work modified through experience. There was a claim made that the curve cannot be calculated. I do not believe that. If normal fixed advance for a Commando is at 29 degrees BTDC, the combustion event is probably complete about 10 degrees ATDC. Any advance curve would have to maintain the point of maximum thrust on the piston.