Pointing back to points :
I had no problems when I was running points , love the smooth tick over and power below 3000 rpm of electronic ignition though.
How about the 123 evo on a modified engine?

Mark,
nothing causes 'pre-detonation', since it does not exist.
However, an engine may suffer from either 'detonation' or 'pre-ignition'...

https://www.savvyanalysis.com/articles/ ... e-ignition

...although I do not agree with the author's statement that all engines can withstand extended periods of detonation without suffering damage.
I've seen too many A series engines that have not survived an inaccurate ignition timing setup.

Thanks for that information Ken.
I am only getting a "tinkling " noise at a certain mid rev range when accelerating hard. Maybe this is not a problem as it performs very well when timed up properly. I have an CHT gauge fitted to keep an eye on.

Are You sure the heads don't leak at the barrels. This wil give the same simptomes..
or the exhaust manifold which leaks just a little...

One my friend has same kind of behaving with MCC ignition. Looked with strobe, the advance was very odd, it altered too much even at idle and more at high revs. Ordered new one, swapped that an all odd behaving disappeared...

The ignition was sent back to MCC, they tested it and sent back a new unit. Haven't test that yet because it arrived about month ago...

My 652cc big bore runs with a simple points assist electronic ignition that cost about £20 from EBay and is timed close to normal advance settings as recommended by Ken and others and suffers no pinking - beauty of these are you can revert back to points easily if suspect......tbh I've tried all sorts of ignition - lumenition, standard points, 123 and points assisted and in reality they don't make a massive difference to performance except for cold starting using electronic versions and I wouldn't bother with any of the more expensive versions again.....

my experience : i have a 650 big-bore & I use the famous 1-2-Spark ignition - I also have a 123-ignition mounted on the same engine. When I swap from 123 to 1-2-spark and back I notice quit some difference - once you use a 1-2-Spark you don't want any other system ! Noticeble increase in torque. In the beginning I had some pinking at full accelleration at certain rev's, you connect to your laptop and retard a little in this region and problem solved. Got 1-2-Spark on both my running cars - very satisfied with this system, no malfunctioning so far.

I wouldn't compare any programmable ignition to non-programmable or even to 123-evo where you can only choose from 16 different ignition curves...

123-ignition, NG-nition, MCC-ignition, etc, are practically "only" substitute for points. And even with points, you can alter curve more than with those substitutes...

Retarding the ignition is not the way forward, fit points back and do your tuning with them.

Very carefully dynamically set the timing up again today. Whatch that Cylinder Head Temperature gauge climb when the engine pinks
On my regular route before well off the clock, now cannot get near the top speed of points only about 65 on the flat slowly creeps up to 70 top. The car is not fast or as much fun anymore but I really like the bottom end torque as I don't slide all over the place getting out of my steep grassy drive and it's so much better in slow moving traffic.
Surley it must be possible to get the curve remapped Are these units hackable