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Got the bike on the dyno for a short time today. We made a real soft first run just to make sure everything was good with the drivetrain and the new motor. All went well and it was clear the bike was on the rich side of things on the main jet. We didn't make any changes as it was more of a shakedown pass then anything. We made two more passes and had some problems with the sniffer/gas analyzer so I couldn't make any changes and then be able to see the affect they had.

So all in all I am happy as I found out that all of the motor/trans work I did held together on the dyno. Checked the hp on the last two passes and both were 110 rwhp @ 7000 rpm with a great power curve that had no dips or spikes in it at all and created power nice and steady all the way to the rev limiter. I have the rev limiter set at 7000 rpm, but may play with it after some research on what will be a safe rpm to rev to without blowing the motor.

We fill that once back on the dyno after it is repaired and some jetting changes, playing with timing a bit and maybe the rev limter we may be able to pull another 10-15 + horse out of the motor.

So for just setting up the motor in my garage by sound and throttle response I am happy to this point with the 110 horse out of the little 82 cubic inch motor.

Scott
 

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Discussion Starter #3
claydbal said:
wheres the video????????????????????????????/
I was playing around with my camrea last week and I think I have it figured out...........I have been real busy trying to get some friends ready for bonneville............I will make it happen.

Scott
 

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isiahstites said:
I was playing around with my camrea last week and I think I have it figured out...........I have been real busy trying to get some friends ready for bonneville............I will make it happen.

Scott
thanks, love the sound of a nasty sportster motor at 7000 plus rpm.
 

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Discussion Starter #5
claydbal said:
thanks, love the sound of a nasty sportster motor at 7000 plus rpm.

You have been real patient about me getting a video up...........I am going to do my best to make it happen this weekend.

Scott
 

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isiahstites said:
You have been real patient about me getting a video up...........I am going to do my best to make it happen this weekend.

Scott
real patient? lol. thanks dude, cant wait.

dennis
 

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Discussion Starter #7
Ok, I finally got some video of the bike today. I bled the brake today so I thought I would take it out for it's first run.

Video one is 1:37 long and you can really hear how good the bike sounds and video two is 1:50 long and was added because it was kinda hard to see the bike with all the cars parked along the street.

I have'nt done much work to the bike lately as I have kinda been taken a break, however it is almost 100% race ready. I still have to do some small minor stuff to finish along with saftey wiring the bike.

Scott

#1
http://www.youtube.com/watch?v=NWAvkV3TyHM

#2
http://www.youtube.com/watch?v=HqdzIWy6MFU
 

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Discussion Starter #10
This post wa from a few weeks ago but the site was down.


I got as far as I could this afternoon on the dyno. My final number were 122.7 hp and 95.5 ft tq. I got rid of the dip in power at 6600 rpm by tightening up a loose connection on one of the coils. That was not the only thing that loosened up and had to be tightened......dam Harley's! I got the a/f as close as I could, it is about 13.5 at 4000 rpm and slowly tapers to about 12.5 +/- as it gets to redline at 7500 rpm. I could not get the a/f as good below 4000 rpm because the bigger intermediate jets I ordered are back ordered. I drilled one intermediate out to .041 which helped, but did not completely fix the condition. Good thing is once I am out of first gear the motor should not see to much of 4000 rpm and below. I played with the timing a little bit and got a few extra horsepower out of the motor, however I may have got more if I would of made a few more passes.

I feel there is little bit more hp and tq in the motor if I did some more fine tunning, but it is good for now. I definately feel a good experienced dyno tuner could exceed what I have done as I am just a rookie tuner.
For now I am very happy with the numbers and all that is left to do is race the dam thing!

Scott

Horsepower only


Horsepower and torque........not sure what happened to the dyno/printer with the torque line??




And here was my next post but the site was down again




Well guys, NRHS saw the dyno sheet and they said we are glad you are happy, but we are not! They are going to send me the specs for the exhhaust they built on the dyno. They say after seeing the sheet.........wait a second I will copy and paste what they said...............be right back........read below.



Scott, I'm glad you're happy with the numbers, but I'm not. That motor is capable of well over 130hp, and now that I can see your dyno sheet, I know exactly what it needs to get there.

Take a look at this sheet: (it is at the bottom of the page)



This motor is a twin to yours. Same bore, same stroke, same heads, same cams, same carb, etc. There's one big difference, and that's the exhaust system. This bike uses an exhaust system that I designed specifically for this motor and specifically for high rpm power.

The best way to evaluate what an exhaust system is doing is to look at the torque curve. The shape of the torque curve is essentially a map of the cylinder fill. On a motor like this, where exhaust augmentation is a big factor in the cylinder fill because of the overlap in the cams, the torque curve tells you a lot about what the exhaust system is doing.

When you look at your torque curve, you can see that it's filling the cylinder best very early in powerband, and then slowly tapering off as rpm builds. The exhaust system is pulling best at a very low rpm.

Now look at the chart I just posted. The torque is peaking way up high. Doesn't run well down low, in fact it has a pretty big dip in the middle. The exhaust is designed to pull at high rpm.

Remember, horsepower is just torque times rpm. To the extent you can make your torque at higher rpm, horsepower will be higher. In other words, to make more power, you need to move that torque peak to the right on the chart.

Right now, you've got an unhappy marriage between your pipes and your cam. The intake close event timing on your cam is optimized for 6000rpm and up. Your pipe is pulling at something much lower than that. You need to get both of those things onto the same page. That will put you north of 130hp, No doubt in my mind.

I'd be happy to send you dimensions for the pipes.

That hole in the middle of the powerband that these pipes cause is due to reversion. The whole idea of the Thunderjet is to deal with that reversion. It allows you to back down the main to band-aid the reversion, but then replaces the fuel at high rpm where the pipe is working. Thunderjets are basically a crutch for unbaffled drag pipes. But it really doesn't matter much if it goes fat and shoots ducks through the mid range on a Bonneville motor. You pass through that rpm range once in first gear and you never see it again.
 

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Great Post!!!

Thanks for keeping us updated with the build. By reading the letter from NRHS, and reviewing my dyno charts, I can see where I need to make changes to my pipes.

Thanks again.
 

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Discussion Starter #12
DEVILDOG said:
Thanks for keeping us updated with the build. By reading the letter from NRHS, and reviewing my dyno charts, I can see where I need to make changes to my pipes.

Thanks again.

No problem and Semper Fi!
 
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