Tell me about the EMS tuner, does it replace the original M&M system? Is there a link to it?
Two separate things going on there Mark. A few years ago I started having Marelli issues that were compounded by parts getting harder and harder to come by. I was never a Marelli hater. It had its limitations but if one were familiar with and didn't go beyond its limitations it was fine. But parts availability and obsolescence issues are tough to get over if you're ever stuck on the side of the road or out of town somewhere. So I de-Marelli'd the bike and converted it to Delphi. 2005 vintage Delphi. Harness, ECU, gauges, battery tray, etc. Really not a bad job if one is so inclined. After the fact I wish I'd gone a generation newer and found 08 vintage parts. Could have done ABS also if I'd done that. But (as is often the case) I digress.
So the bike was changed to Delphi. Still had to do engine management though.
A long time ago, like a decade maybe, Revolution Performance came out with a kit called Precision EMS (engine management system). I like it a lot. Had it on my SEEG, did it on my Road King, and when did the Marelli to Delphi swap used it on the Road Glide. It's a surprisingly "smart" and flexible system that just makes its version of tuning easy.
Unfortunately the kit never took a strong hold in the aftermarket and after a few years marketing the package Revolution Performance allowed the package to fade way. That's still what's on my Road Glide now though. It makes for an interesting first start up after engine work.
This bike went from an almost stock 95" bike. Only internal difference was a small cam change that, itself, wasn't that much difference than the 203s it had out of the box. It now went to the 625 cams, fancy head work, a butt ton more compression, way different pipe, etc. Started the bike the first time and the system started taking big swings at compensation. You'd hear RPMs dance up and down, it surged and worked and gagged and probably even waddled a bit. Then it slowly began to even out. After seven or eight minutes of idling on the table lift it was butter smooth.
First ride saw it do a bit more adjusting on its own. You could feel it changing over the first 10 miles or so. After that any changes being made were subtle enough I couldn't notice them. All that got me to a point that the bike runs pretty much as I expect it to though.
Sure, I really good and expensive dyno tune could and no doubt would find me just a little bit more. Especially at the extremes. Tuning for numbers. But this was easy, took 10 minutes then 10 miles of my time, and the bike runs well. My Twin Tec tool tells me AFRs are spot on now. I'm happy. It's unfortunately not a package we can get anymore though.