Puzzled about the stronger/cut springs and their effect.
The whole reason for retarding is to facilitate starting (so it doesn't try to go backwards) and by being late in power stroke it makes the pulses smoother as it expands the combustion significantly after TDC
As revs pick up, that (if stalled from moving) will just get later in power stroke and reduce torque that's supposed to be being made as you open throttle. It does this because the combustion event duration stays the same but the piston is now moving faster. Combustion duration is more or less consistent in spite of rpm, which is why the need to get maximum advance is key to ultimate power.
It effectively lowers compression ratio as the most energy is placed on a piston now off down the bore, likely it will also give incomplete burn and could be influence in the sooty plugs.
To make the engine perform better, that needs to "chase" the piston speed as it increaeses, the aim being to have peak combustion JUST after TDC with the most energy converted to pushing the conrod down through it's most advantageous angle with the crank pin. Holding retard just wastes that energy. I don't see how it has performance benefit.
Probably wise to use std springs if possible in assessing the mixture. Putting variable like this in will likely skew results.
The only effect I can immediately see is by wasting torque opportunity at low rpm, it will then feel faster when it eventually advances, like a two stroke powerband. Thats effect though snd not more power.
