Dyno results hot off the presses!

[Dragonrider]

It's those big, flat power/torque bands that make all the difference. Thats where "more than 2" cylinders nearly always kick butt...most of the braggert bikes have lots of horsepower...but it's in a VERY narrow band.

[GNEPIG]

.. Here is another run after I changed the pilot jets. this time I rode it on the dyno at my work.. man what a powerful feeling!
.. instead of wacking the throttle wide open after 2000 rpms, I opened the throttle more progressively [not as fast as the other guy did] right at 2000 to get a better reading closer to idle
.. it looks like i gained 1 more hp, but the readings look very similar from two [very] different shops.. my fuel ratio still looks a little rich in the middle but it seems to run pretty good on the street.. the two graphs are not quite the same size but the results are nearly the same
i'm psyched up now for some test and tune this thursday night at my local track

[Shuriken]

That's about as smooth and predictable as I would ever expect to see an XS11 get on the dyno. To me, your results are the evidence of a very well-tuned engine. I would love to see those results for my own machine, but I haven't figured out the gremlins yet.

Ben

[pggg]

GNE, that first sheet looks out of whack with stuff backwards and the lines crossing at 6700. The torque curves are way different with 5500 revs over 50lbs torque on the second one. Your bike must have been powerful before you changed the pilot jets with 80 hp just above idle.

[Dan Hodges]

Originally posted by GNEPIG
.. Here is another run after I changed the pilot jets. this time I rode it on the dyno at my work.. man what a powerful feeling!
.. instead of wacking the throttle wide open after 2000 rpms, I opened the throttle more progressively [not as fast as the other guy did] right at 2000 to get a better reading closer to idle
.. it looks like i gained 1 more hp, but the readings look very similar from two [very] different shops.. my fuel ratio still looks a little rich in the middle but it seems to run pretty good on the street.. the two graphs are not quite the same size but the results are nearly the same
i'm psyched up now for some test and tune this thursday night at my local track

Did you use a correction factor on this test?If not,correcting this to the SAE standard for temp,pressure and humidity will give you a correction factor of 1.052 which will give you 84.16 HP,a very good number for a stock 79 Special with a lot of miles.It just goes to show you,that one of these old bikes with a fresh motor,ported big valve heads,big bore kit and a point more compression will make a hundred HP.

[GNEPIG]

... good eye pggg, as i said these were done at two different places the other big difference was that i did the dyno run myself the second time.
and this would be the first time i have done this.. maybe it's the way i opened the throttle ,i dont know if changing the pilot screws would make much difference but it removed the big step between idle and go and i could turn my fuel mixture screws back down to 2and 3/4 out insted of 4 1/2 out that it was before.. it feels better on the street
. studdying the graphs more it looks like that i've gained a little here and there on the harley dyno sheet but the lines look almost the same except where they cross, i will ask questions about this tomorrow.. it's got to be the way i rode it, next time i will do it the way i'm told to.. maybe i'll get another run at it before i take it to the track this thursday night
.. Dan i'm not sure what your talking about but i did see him make adjustments for temp, humidity,baro pressure and elevation. i think the sae was 1.00

[GNEPIG]

.. i talked to people at both shops today and everyone seems to agree that the differences between the two graphs is in the computer programs. at my shop we looked at other graphs from other runs and the hp/ torque lines all cross at the 5200 rpm mark.
.. since almost all harleys red line at 6500rpm it makes sense to put the crossover at 5200
.. the guys at precision cycle will dyno anything as long as the back wheel will reach the drum and their programs are more specific for each motorcycle they test
. neither shop seems to think that it matters where the lines cross as long as the numbers/lines are the same
. i dont know why they have to cross at all, i guess so it looks good on paper

[pggg]

GNE, apparently horsepower is torque x revs divided by 5252, so the lines on a dyno graph should always cross at 5252 revs. That's more mathematics than my brain can handle. Theres tons of complicated torque/horsepower stuff on the net.

[GNEPIG]

.. well pggg i hope to learn more about this dyno stuff. every one else i work with had a two week course on how to use the dyno in school.. i spent my 15,000 MMI money on dope and booze so i have to learn the old fashion way when i can

.. rain out at the track tonight, i'll try again next week

[GNEPIG]

"Ugly" night at the drags
.. made it to the track thursday night, made 6 passes
my best time of the night was my first pass 13.35 @ 104mph
..it felt like it could do better but the bike shifted like an old pickup truck,
I missed second gear on the 2nd pass
I missed fourth gear on the 3rd pass
I missed fourth gear again on the 4th pass
so decided to go easy on the 5th pass made it through the gears just fine for a 13.50et @ 104mph
then thought i would short shift @ 7500rpms on the sixth run only to miss 4th gear again! .. i had'nt had such trouble with selecting gears hot roding around on the streets with this bike ,or this much trouble on other xs11s i've drag raced before so i figured i was having a bad night and called it quits
. these kind of et's are for harley riders .. the bike runs too good to be that slow.. at least i was faster than the "nopies"
.. i going to make some adjustments then maybe i'll try it again

[xs650mike]

I've found my XS11 to be difficult to upshift quickly though I can downshift fast just fine. It seems to upshift a bit better without clutching though.

[GNEPIG]

.. yea mike, i did try the quick shift w/o the clutch on the ride home with much better results, bummer i didn't think of that earlier .. i hadn't been to the track in 4 years and was way too excited ,a beer or two used to help with that but i don't drink any more
bad pic



"The Ugly" lookin pretty good in the dark

[xs650mike]

There's always next time!

[GNEPIG]

.. another dyno run, this time for the "Red" one ..the numbers dont look as good as the "Ugly" but that doesnt stop it from being my favorite
looks like i need to lower my needles one notch, its running real rich in two spots down low.. it could be rich up top also but i'm only going to change one thing at a time, i'll make another pass next week
.. this bike has about 85,000 miles on it, the stock exhaust, stock air box with 2- 1/2 inch holes drilled in the bottom and K&N filter
..79.44 hp@ 7500 rpm and 56.95 ft lbs torque
This is fun, everyone should dyno their bikes

[chevy45412001]

noticed

sorry couldn't help but notice you lost every race but the one you ran by yourself... but i know how that goes happens to me too. do you ever bracket race? much more fun to actually win races. (brackets put you in a handicap so your both eqeal on paper ) I've even smoked a 10 sec. chevelle . But of coarse that was with a 3sec. head start...