Originally Posted by martin10

Just my opinion. But this is the post of the year so far. I am getting too old to waste time overthinking stuff. Or to even care. The rest of you folks can enjoy the excellent info provided by the OP.

Originally Posted by psyshack

You clearly do not understand NOX and petro combustion. Nox is the enemy epa wise of uber eff. combustion. I could take my Civic Hybrid up until the last flash update and drive it right just out of hypermiler speeds and get 80 mpg all day long out of it with the help of a Atkins Cycle and all sorts of mechanical and control tricks of which Harley hasn't a clue about much less specing a timing chain right. Or basic 1990's cam control. So what does that leave them with? Your st control which is a no brainier and basic ignition control at a pre WWII level. I own a vintage modern motorcycle powered by a advanced lawn mower engine..... lololololo

What Harley is doing is putting a ton of egg into there cats. Cats are amazing devices! But they can be over done. And over done is what MoCo has done.

My testing looks at the tail pipe emissions, exhaust temps where ever I place a sensor. Along with the intake temps, volumes and velocity. And diff across the filter media. with a look into the manifold velocity's and fuel metering bandwidth. Harley is getting there numbers from bad cat design ment to kiss the epa's ***.

Harleys Cat design is what Yamaha should have used in my Yamaha RZ350 OEM pipe design. The USA spec RZ350 2 stroke had cats built into the pipes. Only USA 2 stroke to ever have such BS in the world. All to make the cali dick suckers happy.

Originally Posted by smitty901

News flash the 107 M8 runs just fine. Invent all the problems you want .Won't change fact. But of course everyone knows more than those that designed it.
Building tuning changing is part of owning a Harley but not necessary.

Originally Posted by bwoltz

Actually it more like I don't understand what you are saying and you don't understand what I'm saying.. Yes Nox is one of the evil things the environmentalists don't you motor vehicle spewing.

Also it's called the Atkinson Cycle.

http://www.animatedengines.com/atkinson.html

The turbo charged toyota Atkinson Cycle version is simply variable cam timing as I understand it but please correct me if I'm wrong.

The Prius version and I would assume the Civic Hybrid use custom valve timing which results in a motor with a very narrow power band.. I'm sure HD owners would love that. Remember all hybrids IC motors need to do is drive a generator.

So does the Atkinson cycle motor eliminate the requirement for a catalytic converter?

How easy is Atkinson Cycle to implement on a motorcycle? Variable cam timing and turbo? Special cam timing and narrow power band?

You sounds like you understand emissions.. How did HD over do the cat? They needed to put it somewhere and at a reasonable cost.

How about some suggestions as to implementation?

Originally Posted by Deuuuce

Some corrections: Most hybrids use the ICE to directly power the drive wheels. A FEW hybrids use the ICE only as a power generator like the Chevy Volt.

The Atkinson Cycle is where the intake valve remains open a bit for compression cycle, making the engine more fuel efficient at the expense of power,

"The effective compression ratio is reduced (for the time the air is escaping the cylinder freely rather than being compressed), but the expansion ratio is unchanged. This means the compression ratio is smaller than the expansion ratio. Heat gained from burning fuel increases the pressure, thereby forcing the piston to move, expanding the air volume beyond the volume when compression began. The goal of the modern Atkinson cycle is to allow the pressure in the combustion chamber at the end of the power stroke to be equal to atmospheric pressure; when this occurs, all the available energy has been obtained from the combustion process. For any given portion of air, the greater expansion ratio allows more energy to be converted from heat to useful mechanical energy, meaning the engine is more efficient."

It does NOT mean the cat can be done away with.

Originally Posted by jgrohio

After a 60 degree day in Ohio and Pa and getting in some much needed wind therapy I come home enjoy a few bourbons and read this and I'm lost lol. All I know is my M8 ran great today lol