This is my Dyno chart from earlier this spring. My bike is an '04 1200C with modified stock pipes, Forcewinder, and a Yost kit.

I want to put cams in next (see engine, bottom end section) but still trying to decide what cams to use. Not sure what makes the jumps in the chart, thier Dyno, or my primary chain too loose.

I am happy with the results though. 79.3 HP and 81 LB/FT

http://image60.webshots.com/60/0/23/95/476202395RAmLcZ_fs.jpg

Okay, I'm an idiot and can't post pictures. so you'll have to click the link.

Try posting your picture (dyno sheet) in your gallery and then linking it here. I can not seem to view whatever page you linked.

Sorry, the new one should be here

http://photobucket.com/albums/a213/cadiero/?action=view&current=DynoChart.jpg

i think 79 HP from a 1200 sporty is very good. i race my buddy that rides a yamaha warrrior with a lot of dyno work at [V&H] he got 83 HP from i think around 1700 cc. yes i could beat him until the last dyno job, we tie now.:smoke
all i have is a cycle shack slip on and SE air filter and jetting i did myself. he spent prolly 1,500 bucks on his.:roflblack

You've got killer numbers, and a super tq curve. Not sure how you did it really - I've got the 2:1 Supertrapp and the same carb kit as you and I'm about 3 points lower on peak numbers and you have about 10 point more TQ at 2500 than I do. Truely impressive.

What main jet did you end up with ?

I notice that your dyno sheet says "DIN" horsepower and torque.

Mine says "STD".

Can anyone tell me what the difference is?

I may be wrong, but I think STD is SAE corrected rear wheel hp and DIN may not be corrected, thus slightly high readings.

Figures do seem a bit high.

When I dyno'd mine last year it got 81 hp and 76 ft. That was with the .551 cams 42mm Mikuni and the SE ignition.

If I'm not mistaken the DIN hp is at rear wheel. I may be wrong though.

I notice that your dyno sheet says "DIN" horsepower and torque.

Mine says "STD".

Can anyone tell me what the difference is?

Here you go taken from a website.

SAE Net Horspower
In 1972, American manufacturers phased in SAE net horsepower. This is the standard on which current American ratings are based. This rating is measured at the flywheel, on an engine dyno, but the engine is tested with all accessories installed, including a full exhaust system, all pumps, the alternator, the starter, and emissions controls. Both SAE net and SAE gross horsepower test procedures are documented in Society of Automotive Engineers standard J1349. Because SAE net is so common, this is the standard we will use to compare all others.

SAE Gross Horsepower
This is the old process that American manufacturers used as a guide for rating their cars. It was in place until 1971. SAE gross also measures horsepower at the flywheel, but with no accessories to bog it down. This is the bare engine with nothing but the absolute essentials attached to it; little more than a carb, fuel pump, oil pump, and water pump. Because the test equipment on the engine is not the same as in SAE net, it is impossible to provide a mathematical calculation between SAE net and SAE gross. As a general rule, however, SAE net tends to be approximately 80% of the value of SAE gross. SAE J245 and J1995 define this measurement.

DIN Horsepower
This is a standard, DIN 70020, for measuring horsepower that very closely matches SAE net. The conditions of the test vary slightly, but the required equipment on the engine and the point of measurement (flywheel) remains the same. Because the test conditions are so similar, it is safe to divide DIN horsepower by 1.0139 to arrive at SAE net. This value is so close to equal that for all but the most technical purposes DIN and SAE net are interchangeable.

The Dynojet software gives you the option of plotting the results in SAE, STD, DIN, EEC, or actual horsepower. All are different correction algortihms (except actual, which is uncorrected).

The correction algorithm corrects the measured results back to a set of reference conditions. The weather station, which is part of the dyno, measures temp, barometric pressure, & relative humidity, comes up with a "correction factor" based on the difference between those conditions and the reference conditions, and applies that correction factor to the measured results.

For example, if I have an SAE correction factor of 1.10, and the bike makes 100hp, the plotted result will be 110hp, which is what the bike theoretically would've measured if it was tested under the reference conditions (where it would've had a correction factor of 1.00).

Each of these correction algorithms gives a different result. Many times I've seen shops that will go through the list when plotting a result and pick the one that serves their purpose the best. For example, if they're trying to sell a job, they may choose the one that shows the lowest. If it's a bike they've already done the work on, they may choose the one that shows the highest.

A tell-tale sign is when you look at the sheets a shop is showing in their dvertising and you see a mixture of different correction standards. They're picking and choosing to make them look better.

Some people do worse things, like artificially heating up the weather station prior to doing the pulls.

SAE is the most widely used in the US, so that's what we always use.

That is what I thought. The HP and TQ figures from HD are at the flywheel and obviously the ones we are all able to get are at the rear wheel (through the drive system, etc).

I have heard that typical variance from rear wheel to flywheel on a Sportster are bout 20% depending on the model (belt angle and tension being one factor that differs). Aaron, does that sound about right? So, someone on here with a 100 hp (rear wheel dyno hp) would have the equivilent of 120 hp at the flywheel (like the factory measures).

I have heard that typical variance from rear wheel to flywheel on a Sportster are bout 20% depending on the model (belt angle and tension being one factor that differs). Aaron, does that sound about right? So, someone on here with a 100 hp (rear wheel dyno hp) would have the equivilent of 120 hp at the flywheel (like the factory measures).


I actually went through and calculated all of this at one point because I was curious what my bike was making at the crank. I had a magazine with a rear wheel dyno pull on a stock 2004 1200, so I compared it's peak ratings to the factory's peak ratings (70hp and 79ft-lbs) to come up with a percentage of how much power was lost in the drivetrain. I can't remember it exactly, but I want to say it was 9 or 11% - not 20% though, I know it wasn't that high. I think it came out that at the time my bike was making something like 72 rwhp and it would have been around 80 or 85 at the flywheel. I'll see if I can dig up that mag again and come up with some numbers.

Don't hold me to these numbers, I'm just going by my memory.

I had a guy tell me that his 05 1200 Custom with a stage 1 (SE II's, S&S A/C and rejet) had a dyno done and that his read 80 HP...

Can that be right?

Loco
So. Cal.

Thats what my 05-1200R has done to it. I got 81 at the crank and 74.6 at the rear trie.....

drummer ....

How did you get the 81 HP figure at the crank?