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Good question Drew, I was thinking about that too.It's something that's not claimed generally by most types of system. They normally go with fatter / hotter spark, improved starting, improved high speed accuracy etc, making it difficult to see if they have considered more in depth issues and completed a design to address something very specific. They appear, in this field generally, to cover this sort of stuff with words like "improved driveability" which could mean any number of things. The Boyer has always seemed a very competent system but ultimately it may be worth posing a specific question to them to understand, in their view, how they approach something like this.It's complicated by the Honda original, in my view, being a very good mechanical design with some clearly very subtle qualities that are very hard to improve without very specific knowledge. The area that would seem in the original fit to be most influential is the length of spark, ie duration of the spark event. Honda appear to have designed in a specific length that would benefit their combustion chamber requirements. The bigger is better school of thought may trip up on something like this. This is pulling together what I view as happening to produce error; with a still relatively low piston speed at around 2/4000rpm the ignition reaches its maximum advance. The time of piston travelling during the period of spark initiation until piston reaches tdc, if it's more time than spark duration, then the spark will have completed prior to tdc. It looks to me that Honda are trying to cover this area of interest by designing in a "long" spark. If a replacement system shortens the spark, it looks like this area is the most vulnerable to complications. So anyone claiming a shorter ignition duration will appear suspicious. It's notable ( I think it's correct) that Honda delay the max advance rpm point for the 400 Four above those of the 500 / 750 so they are also massaging this point as well to avoid the detonation as I view it. I think the Boyer doesn't change this spec but also uses it for the whole range of these four cylinder engines.If you then add in that mixture curve that we can see has the possibility of going very lean (peaks about 15.7 parts air to fuel ratio) it all meets at this critical point, making it very marginal to get a clean combustion event completed.