25 years of sportbike development - Page 5

Tmall · 08-23-2009, 12:29 PM

Cylinder filling is just about as efficient as it will get.

It has a giant pump pulling the air in. Aside from forced induction, you don't get too much more power from head work.
If all it took to increase tq was to polish your intake ports and have the intake velocities be spot on, wouldn't the manufacturers be doing it?

I suppose decreasing losses would count, suzuki did it on their bikes by reducing pumping losses in the cylinders themselves.

Falls under the law of diminishing returns.

Dave · 08-23-2009, 12:34 PM

i actually was referring to forced induction. and kawasaki already hand finishes their intake ports

Tmall · 08-23-2009, 12:36 PM

Gotcha.

Forced induction mimics higher displacement.

No Worries · 08-23-2009, 12:58 PM

Torque X RPM divided by 5252 = HP. You have to increase torque and/or RPM to get more HP. But there is a maximum speed that the piston can travel at, as it accelerates from 0-100MPH (or more) and then decelerates as it goes up and down.

Changing the stroke changes where the torque peak occurs. For the riding I do, I'd much rather have an early R1 (long stroke) than a newer one. And for racing across an intersection, a cruiser, with it's torque peak right off idle, will win without any fuss. Plus, they are impossible to stall at a light.

karl_1052 · 08-23-2009, 04:51 PM

Quote:

Originally Posted by No Worries

And for racing across an intersection, a cruiser, with it's torque peak right off idle, will win without any fuss. Plus, they are impossible to stall at a light.

I would take that challenge.

derf · 08-23-2009, 05:02 PM

Quote:

Originally Posted by karl_1052

I would take that challenge.

Yup, based on just an engine vs engine comparison maybe, but when you look at the ability of a cruiser to take off vs that of a sportbike. A cruiser weighs in at between 500 - 1000 lbs, a sportbike is in the 350-450 lb range, that is alot less weight to move around. There are also a host of other factors that will come into play too

08-23-2009, 12:34 PM	#42
Dave Chaotic Neutral Join Date: Feb 2008 Location: Cherry Hill NJ Moto: GV1200 Madura, Hawk gt Posts: 13,992	i actually was referring to forced induction. and kawasaki already hand finishes their intake ports __________________ TWF Post whore #6

08-23-2009, 12:29 PM	#41
Tmall Aspiring Rapper Join Date: Nov 2008 Location: Halifax, NS Moto: '12 CB1000R Posts: 3,569	Cylinder filling is just about as efficient as it will get. It has a giant pump pulling the air in. Aside from forced induction, you don't get too much more power from head work. If all it took to increase tq was to polish your intake ports and have the intake velocities be spot on, wouldn't the manufacturers be doing it? I suppose decreasing losses would count, suzuki did it on their bikes by reducing pumping losses in the cylinders themselves. Falls under the law of diminishing returns.

08-23-2009, 12:36 PM	#43
Tmall Aspiring Rapper Join Date: Nov 2008 Location: Halifax, NS Moto: '12 CB1000R Posts: 3,569	Gotcha. Forced induction mimics higher displacement.

08-23-2009, 12:58 PM	#44
No Worries Keyboard Racer Join Date: Feb 2008 Location: Mile High City Moto: Old Superbikes Posts: 1,016	Torque X RPM divided by 5252 = HP. You have to increase torque and/or RPM to get more HP. But there is a maximum speed that the piston can travel at, as it accelerates from 0-100MPH (or more) and then decelerates as it goes up and down. Changing the stroke changes where the torque peak occurs. For the riding I do, I'd much rather have an early R1 (long stroke) than a newer one. And for racing across an intersection, a cruiser, with it's torque peak right off idle, will win without any fuss. Plus, they are impossible to stall at a light.