what is the difference in hp between the xr1200 which they say is 90hp
and the 1200 custom?

 

HD usually quotes only the torque for a 1200 at 79.1 ft-lbs, I think the stock horse power is somewhere around 68 to 70.

 

That is crank HP not what it puts to the ground!

 

They still dyno higher horses! I can't remember exactly what I read, but I know that it was 80 something stock HP RW.

 

Both motorcycles are powered by an air cooled 73.4 cubic inch Evolution engine while the 1200 Custom boasts more torque with 79 lb-ft compared to the 73.8 lb-ft made by the XR1200. The big difference in the two engines is in horsepower. Although Harley doesn't publish horsepower numbers for many of their bikes, the XR1200 generates an advertised 90 horsepower. In comparison, the Sportster 1200 Custom typically measures in the low 70-75 horsepower range.

 

Harley rates the 2004+ 1200 engines at 70 crank horsepower (which is not the actual horsepower delivered to the rear wheel).

Here is the information from Harley;

"The XL Evolution 883 engine is rated at 53 peak horsepower at 6000 rpm and 51 ft. lbs. of torque at 4300 rpm. The XL Evolution 1200 engine is rated at 70 peak horsepower at 6000 rpm and 79 ft. lbs. of torque at 3500 rpm, an increase of more than 15 percent over the previous XL Evolution 1200 engine".

A good friend of mine is a long time Harley dealership mechanic and also does a lot of dyno tuning, etc...

He has told me that a 'bone stock' 1200 Sportser (newer model) will put approximately 60 to 62 horsepower to the rear wheel.

 

Then the new sportsters really like a good dyno tune and stage one upgrades i got 82hp to the ground and 78.4 tq with a good 2 into 1 exhaust system add anywhere from 2-6 hp from what i seen

 

thanks for the info
sold my fxd because it was too heavy and didn't like to lean over,always scraping the chassis
the xr1200 is on my fast track to replace my fxd

 

This is how my buddy (4.0 Physics major/mad scientist) explain it to me. Bare in mind we were talking about the Nightster vs. XR1200

First off, the numbers that they publish are rarely 100% accurate.
Second, you also have to realize that the XR is a European model and the Nightster is a North American model.
We each have different standards for our gasoline/petrol that we use, along with emissions systems that are implemented/must be met to appease each continent.
Also, higher compression doesn't inherently mean more power. You have static compression ratios, which are the numbers you listed, and then you have dynamic compression ratios, which change as the piston move up and down in the cylinder wall and the camshaft(s) opens and closes the valves.
Then you have the fact that the equation that you have is a very simplified equation that is the equivalent of classical mechanics to a relativistic problem that is an internal combustion engine.
You have a lot of differences in specific parts of the engine. Piston dish, dome, or flat top size, valve reliefs, and the volume associated with each. Cylinder head differences: shape of the combustion chamber, how it fits with the dish or dome on the piston head, intake and exhaust runner volumes, intake and exhaust valve diameters and angle.
Anyway, to spare you a bunch of technical mumbo jumbo, my guess would be that the XR is, indeed, the latest and greatest, making 90 hp and having a 10.0:1 compression ratio. I think that you're equation is just what's getting you the worst.

 

Not enough in my opinion, it's not significantly more powerful then an 03 1200S. For what their charging I would want at least 100 hp.