In reply to alfadriver (Forum Supporter) :
I've always operated on the idea that the most efficiently run engine should also run the cleanest but that may not be what the Euro emissions test is looking for. I believe the engines are tuned only to pass the test, not to be optimally efficient.
I can only speak for the tune in the 'Guzzi 8v engine.
There were two issues that were the problem, one was a snatchy throttle just off of idle and the second was a surging between 3500 to 4000 rpm.
There are two guys that I know of who write the best maps for these engines, one guy is in Germany (I'm running his map) and another in Australia. The fix in both of their maps is to richen up the fuel in the lower rpm ranges and to turn off the O2 sensor and run the engine strictly on throttle position and manifold pressure. They both also add more timing.
The guy from Germany mentioned that the factory tune was pretty out of whack from one cylinder to the other as well. It's a flying twin so both cylinders see the same amount of cooling air so both should be fueled pretty closely but apparently these were way off.
The surging at rpm is fixed by shutting off the O2 sensors (which I did in software long before I started running the improved map) because the ECU transitions in or out of (can't remember off the top of my head) using the O2 sensor feedback right around 4000 rpm.
The bike is much more ridable now, no more snatchy throttle and no more surge. More power but more fuel consumption. I'll gladly take the mileage hit to improve the way the engine runs.
For what it's worth, the factory has also released upgraded maps for these bikes which do make some improvements but nothing as good as the aftermarket maps. Probably because the factory has to remain emissions compliant.
As for the ECU foolers, I've never dealt with them personally. Guzzitech swears by them but they like Power Commanders too and most guys who use Power Commanders end up taking them off. Pete Roper, the Aussie guru of all things 'Guzzi has shared the aftermath of a few engines prematurely worn thanks to overfueling from these add-on products.
The reason the new Euro standards are killing big bore, air cooled bikes is because of the uneven cooling affecting oil consumption and increasing emissions. "Guzzi tried to fix this with the oil cooled 8V engines but the latest standards killed them. BMW has been trying the same with added cooling on their engines. Most manufacturers are giving up and building smaller engines or going multi-cylinder.
It's also Moto Guzzi so it could just be plain old incompetence. Generally they're fantastic bikes once you spend some time fixing all the stuff the manufacturer forgot.
Motorcycles have left the factory with horrible tuning since the dawn of motorcycling. There's a whole industry built around making them run properly once they get into the owners hands.
Heck the 80's CB900s could pick up nearly 10hp just by re-jetting them.
That's all I know about the situation. I know you understand a lot more about this sort of thing than I do and there's a lot more going on with emissions requirements than I understand.