You're actually introducing too many variables. If you have two identical engines and one has lighter internals, it should make more horsepower at a given rpm and have a higher peak horsepower (allowing for air/fuel delivery).

 

Good explanation!

 

I've been thinking about buying a Power vision myself. The only thing i dislike is the fact that it dont run closed loop. Is that a problem?

 

It is a good explanation. But that is regarding the flywheel which is a rotating assembly AFTER the engine. Like the driveshaft, etc. It changes the characteristics of the engine. The flywheel is just along for the ride.

I'm referring to lighter internals inside the engine - the rods, pistons and crankshaft, the pieces that "create" the rotating force.

 

 

Sorry to split hairs (kind of), but no pieces of your motor create force... The combustion of air/fuel creates force. All the moving parts of the engine are "along for the ride" so to speak. They are being moved by the force and in the process channeling the force to the next part. From piston>rod>crank>compensator>chain>clutch basket>clutch plates>clutch hub>trasmission>puley>belt>pulley>tire>ground

Making any one of those parts (or any part between the combustion and the tire) lighter, whether its inside your motor or not, will create a higher peak hp/tq at the wheel. Most of the time to small of a difference to to be even considered on a street bike... Unless your going from 10lb connecting rods to 6oz connecting rods or some unrealistic and dramatic change like that

Think of it as your engine using its power to do 2 things.
#1 Move itself and the drivetrain
#2 Move the bike.
Less rotating mass of the drivetrain or engine means less force required to move it, less force means less work done moving it, less work means less energy expended to move it, less energy expended means less power was used. If you decrease the power required to turn the engine internals by 10% (good luck with that lol) then you increase the power that makes it to the wheel by 10%. The overall power didnt change, but the usable power did.

 

I'm going to disagree. I believe (think) that lighter rods, pistons and crankshaft will measure higher horsepower (measured at the flywheel) than heavier at any given rpm. Equal force applied (combustion chamber) transmitted through lighter components will show higher horsepower.

 

It does in the realm of the narrow band O2 sensors, and you can buy the wide band kit to cover the whole enchalada.

 

I think we're on the same page here, I was just splitting hairs about the "parts creating power" comment. They transfer power, which is created by the combustion.

But as you and I both said, less mass on the parts of the rotating assembly will show more power measured downstream from said parts.

 

All those variables are proven facts, through experiences of several race teams. I have no idea of why you think less weight will make more power, it can't, given that nothing else changes. The motor still consumes the same amount of air fuel mix.
It is a known and proven fact that a lighter crankshaft accelerates faster off a turn on an oval track, and the formulas for this weight reduction show exactly those results. It is not more horsepower, it is less mass to spin up. you can find the math in Herb Adams Chassis book.