There is much to think about here. I'm no engine designer, but I see two separate issues/problems/compromises going on.
Allow me to explain (and it will have little or nothing to do with what type of ignition you use).
The first is variation of the cam in relation to the crank. I don't care how you drive the cam (belt, chain, gear) there is variation.
Belts and chains have slack, and gears have clearance or they'd explode when the engine got up to operating temp.
We ran 204 mph at the Texas Mile with a Honda CBR1000 street bike. Guess what? The cams are chain driven and have spring loaded tensioners. We did not melt a piston. It starts and idles perfect. We even used NOS and made well over a dozen passes without issue, and it's still ridden to work almost daily.
So I'd like to measure the variation of a Goldwing cam and crankshaft on a RUNNING engine. I don't care one tiny little bit about rotating it by hand. That doesn't matter to me. All that matters is what happens from 1000 rpm to 10,000 rpm. It can be done a few ways and I'm working on the best method yet.
Second issue....Variation of the left head compared to the right head. Why care about it? Because if the cams are bouncing back and forth from their correct relationship to the crankshaft, then there will be variations of the left and right cylinders. It should affect valve timing as well as ignition events.
We can accomplish both tests at once using three triggers. One crank mounted and one on each cam. Fire up the engine and measure how much variation each of them have using the CRANK as the reference part. If there is a substantial timing variation it could cause running issues or even detonation.
I have theories about the 5-10 degree variation. I believe they were measuring timing swings due to advancer shaft movement. I also know for a fact there is at least 7 degrees of variation on Hall Effect triggers which are used for almost all electronic ignitions.
A fair comparison is to measure variation of the three engine parts, then measure spark variation using an accurate timing light and compare points to magnets, and magnets to optical.
Sorry for the long explanation. I was driving most of the day and had too much time to think :whistling:
