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Discussion Starter #1
HP = 42.16
TQ = 49.80

Bone stock, clean air filter, it will actually drop if I remove it. Rear tire is only 1000 miles old. I am not even coming close to factory, which is supposed to be close to 50HP and close to 60 torque. The sources you get the number from vary a little.

Before modding this bike into a bobber, I would like to find out what could be wrong. With only 12k you would think it would be broke in by now, and based on how clean the engine was inside indicates it saw at least normal oil drain intervals. It also runs very strong and smooth.
 

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Which bike was it from your stable?

Anyways, compared to the numbers you're quoting, the dyno numbers seem fine. You're probably looking at numbers for the bike for hp/tq at the engine and not at the wheel. There's going to be some parasitic loss. Then add to that the variance of weather (heat/humidity) and the calibration differences of the different types of dynos, you're probably just being paranoid. If it'll help you feel better, you can always do a compression and leak down tests to make sure rings and seals are good.
 

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Discussion Starter #3
That sure would help: 2006 Vulcan 900 with 12k miles. It had a wiring issue with the stator that I fixed and all is well. I did the compression dry and wet and it was spot on per the book. No abnormal leakdown or valve leakage.

Arn;t the number the factory publishes the real HP / TQ? I asked the dyno operator if we could measure just the engine and he said there is no way to connect it.
 

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That sure would help: 2006 Vulcan 900 with 12k miles. It had a wiring issue with the stator that I fixed and all is well. I did the compression dry and wet and it was spot on per the book. No abnormal leakdown or valve leakage.

Arn;t the number the factory publishes the real HP / TQ? I asked the dyno operator if we could measure just the engine and he said there is no way to connect it.
As others have said Max HP& Torque are made at the engine. There is a reason its called brake HP ie. what it take's to brake or stop the motor.

Back in the early 70's I think, the factories went to net HP which included water pump/alt/power steering pump/torque converter/flywheel ect. but still not at the rear wheel.

Rear wheel losses 10-25 % depending on trans,drive system, tires-n-wheels.::frown2:

Now you know why a fair number of 900 owners try to get an extra 5-6 HP, most of the increases go to the rear wheels. A few are able to get more 7-12 HP.
More HP or less weight increases the HP to weight ratio=quicker:wink2:
 

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i don't understand why you need HP when riding a cruiser, consider a diesel locomotive pulling 200 loaded box cars, it has 0 HP
 

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i don't understand why you need HP when riding a cruiser, consider a diesel locomotive pulling 200 loaded box cars, it has 0 HP
Er... where did you hear that? There's GOBS of horsepower. The diesel engine itself (which drives the generator) can be in excess of 6,000+ horsepower. And it's not uncommon for each individual electric motor that drives the wheels to be in excess of 750 horsepower; even 1,000+ horsepower. Obviously, the torque is king here (Many locomotives can start a load with over 100,000 ft/lb's of torque), but there's still plenty of horsepower. In fact, the difference between DC actuated trains (DC generator drive by diesel engines) and AC actuated trains; is expressed in horsepower. Any old train mechanic will tell you that DC trains are good for up to 3,000 horsepower; and AC trains are good to go above 3,000 horsepower. It's probably accurate that at a complete standstill, a train has perhaps 100,000 ft/lb's of torque when the engineer pulls the lever, and 0HP; but that's only for a fraction of a second. The minute it lurches forward it's got horsepower; and lots of it. Horsepower climbs as the train accelerates.

Horsepower is a mathematical equation. It's essentially torque; but with the factor of time added. A fixed torque value x a fixed time value = 1 horsepower. (Those values are determined by who is doing the measuring and on what scale. Imperial horsepower is 550ft/lbs per second for example). Something with zero horsepower mathematically cannot move. When you take torque, and you start adding motion, you get horsepower. My favorite way I've heard it explained is "Horsepower is how fast you hit the brick wall, torque is how far you take the brick wall with you". Horsepower has a disproportionate effect on top speed, and torque a disproportionate effect on acceleration from zero. Hence electric cars, which have 100% of their torque available from a standstill, having acceleration that gasoline-powered supercars could only dream of. But because electric motors don't have a ton of horsepower (and manufacturers usually don't include transmissions in electric cars), their top speed is limited.

OP; those numbers are fine. Manufacturers are always super optimistic with power ratings. Most vehicles can assume about a 15% drivetrain loss. Which is spot on where you're at.

Back in the day, it was way worse. During the muscle car era, they'd test engines in ideal ambient conditions with no exhaust, no air intake, no water pump or alternator, etc., and right at the flywheel. That's why the salesman would tell you that Hemi had 400 horsepower; but if you ever took it to a Dyno, they'd say you had 210 horsepower at the wheels. Today's V6 cars are actually faster AND more powerful at the wheels than most of the big V8 cars of the 50's, 60's and 70's. The early 60's 302 V8 Mustangs for example, would be lucky to get 140hp at the wheels. A V6 3.7L Mustang you can buy today will push 280 at the wheels (and it's advertised at 305hp).

With a few bolt on mods you can get those numbers up quite a bit if you want. You can also buy a more powerful bike. Lots of options if you want bigger numbers.
 

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i don't understand why you need HP when riding a cruiser, consider a diesel locomotive pulling 200 loaded box cars, it has 0 HP
With 0 HP that locomotive and loaded box cars wouldn't move one inch or even one millimeter.

About the OP's dyno results, they appear to be in line with what other owners have reported, and for the reasons noted in previous posts.
 

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HP = 42.16
TQ = 49.80

Bone stock, clean air filter, it will actually drop if I remove it. Rear tire is only 1000 miles old. I am not even coming close to factory, which is supposed to be close to 50HP and close to 60 torque. The sources you get the number from vary a little.

Before modding this bike into a bobber, I would like to find out what could be wrong. With only 12k you would think it would be broke in by now, and based on how clean the engine was inside indicates it saw at least normal oil drain intervals. It also runs very strong and smooth.
By adding the big 3, there have been dyno reports uploaded on here as high as 60.5 hp at the rear wheel ... that's a huge jump. I did the big 3 on my custom and it ran like a scalded cat, when I got back on my classic, life was a lot more sedate. Dyno reports have been submitted on here after debaffling the stock exhaust .... giving a further reduction over the stock numbers. (around 38hp if my memory serves me correctly)
 

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Discussion Starter #14
By adding the big 3, there have been dyno reports uploaded on here as high as 60.5 hp at the rear wheel ... that's a huge jump. I did the big 3 on my custom and it ran like a scalded cat, when I got back on my classic, life was a lot more sedate. Dyno reports have been submitted on here after debaffling the stock exhaust .... giving a further reduction over the stock numbers. (around 38hp if my memory serves me correctly)
Can you tell me what the "big 3" is?
 
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