How powerful is an 883 Sportster?

[DUMBDOG]

OK, I know I picked on the sporty, but I did start out on a Yamaha R5 back in 71, you are right it was a screamer.

Yes, I know that you can buy a compact tractor for what a HD does cost. But HD does build a fine muffler, the problem is that a lot of people that buy them put on straight pipes or aftermarket pipes which are quite loud. I always have stock mufflers on mine. But in the past if you paid sticker for them
and kept them 5 to 10 years you could usually get back what you paid for them.

I used to put on over 12,000 miles a year on, until I retired that is, now I no longer have the time, to busy on my property getting everything done ready to build. I know a lot of people that put on in excess of 10,000 miles a year.

Most of the riders I know or either working, riding or on a supper run, not the bars.

By the way I finally got the picture thing right.

 

[s1120]

<font color=red>The torque curve has a pretty good dip in the middle which I suspect is a lean condition in the mid range</font color=red>

I would bet you put the stock pipes on that would go away.

 

[s1120]

<font color=red>Now lets take a look at a Jap motor. 998 cc (59.9 C.I.D.) About a 13% increase in displacement, but in a little more efficient configuration. Whoa! 131.6 HP. and 69.5 ft.lbs. at the rear wheel, or in laymans terms about 2.2 HP per cube. </font color=red>

Now if you want a real fair test, put it agenst the Ducati, or the Moto Guzzy. Bolth old world twins.

Ducati Monster...
Type L twin cylinder, 2 valve per cylinder Desmodromic; air cooled
Displacement 904 cc
BorexStroke 92x68 mm
Compression Ratio 9.2:1
Power 57 kW - 78 HP @ 8000 rpm
Torque 73 Nm - 7.4 Kgm @ 6250 rpm
Fuel injection Marelli electronic fuel injection, 45 mm throttle body
Exhaust 2 aluminium mufflers
Emissions Euro 1

MutoGuzzy Cal.
Engine Type: 4 stroke air cooled
Displacement: 1064CC, 90° V-twin
Bore/Stroke: 92mm x 80mm
Compression Ratio: 9.5 : 1
Max. H.P: 74 @ 6400 RPM
Max. Torque: 70 ft/lbs. @ 5000 RPM
Valve System: 2 overhead valves with light alloy push-rods
Fuel System: Magneti Marelli IAW Multipoint phased sequential fuel injection
Ignition: Magneti Marelli IAW electronic digital ignition with inductive spark
Gear Box: 5 speed, constant mesh gears with built-in cush drive

Hmmm./w3tcompact/icons/hmm.gif Its a little early for math, but it looks like they kick HD's but....../w3tcompact/icons/smile.gif/w3tcompact/icons/grin.gif

 

[Thomas]

Hearing not the problem for us Harley riders Wingnnut..its the women,for they adore and fall in /w3tcompact/icons/love.gif w/us no matter where we go /w3tcompact/icons/crazy.gif I guess its just a cure we have to live with. /w3tcompact/icons/wink.gif

 

[Thomas]

And don't forget helping w/the better half new ideas around the home stead. /w3tcompact/icons/eyes.gif

 

[Anonymous Poster]

Whats unfair about comparing HP/CI between engines?

Ducati: 1.4 HP/CI

Guzzi: 1.2 HP/CI

And I would have to see the bikes run to believe it. Manufacturers tend to publish crankshaft numbers. Yamaha touts 150 HP on the R1, and I measure about 126HP at the rear wheel. This dyno makes a liar out of everyone every time. I know that some dyno charts are falsified in advertising, because some of the published charts don't even cross at 5252 RPM. It is a mathmatical absolute that torque and HP curves will cross at 5252 RPM. There is a big difference between crankshaft HP and rear wheel HP. I like it when guys tell me there is something wrong with my dyno, because it measures 40HP on their machine and they figured it should have 75HP. My mechanics refer to it lovingly as "the heartbreaker".

 

[AMP762]

I don't understand how torque & hp can cross at 5252rpm,my tractor won't turn 5252rpm. /w3tcompact/icons/hmm.gif

 

[s1120]

<font color=red>my tractor won't turn 5252rpm</font color=red>

Not for long anyways./w3tcompact/icons/smile.gif But that is true. Rember HP is just a made up number. Tork is the real number, you figure HP from that.

 

[s1120]

<font color=red>I like it when guys tell me there is something wrong with my dyno, because it measures 40HP on their machine and they figured it should have 75HP. My mechanics refer to it lovingly as "the heartbreaker".</font color=red>

You got to love those people./w3tcompact/icons/smile.gif Back in my drag racing days, if I had a dollor, for every "10sec." car I dusted with my 12 sec Mustang, I would be a rich man now. /w3tcompact/icons/grin.gif

 

[Anonymous Poster]

Paul's right. Torque is the measurement of the work being done. HP is torque x RPM / 5252 (a simple calculation). Your tractor has a HP rating, but the torque measurement is a higher number. If you have a B2910 (approx. 29 HP), you can rearrange the formula to get about 100 ft. lbs of torque @ 1500 RPM. If your tractor would rev past 5252 the HP number would probably be higher than the torque reading. Typically, engines with big heavy internal parts produce more torque than engines of similar displacement with lighter parts. The thing that really builds torque in an engine is the stroke of the piston. Almost universally, a longer stroke makes more torque. That is why tractor blocks are reeeally long (long stroke = lots of torque).
Now consider a small gas powered model airplane engine. They are the HP kings, but that is because they spin at godawful RPMs. Get it?