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myvrodrocks
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Discussion Starter · #1 ·
hi all i am at the dyno right now and we are having some trouble.

we have all the data in the computer...but when we attempt the test, the bike says 3000 rpm and the computer says 1600

so when the bike hits the rev limiter the computer thinks we stopped a 7000 and cancels the test.


Any ideas? we have double checked the 30 tooth adn 72 tooth pulley and all the gear ratios are corret.

Please help!!
 

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RICK
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648 Posts
YOU HAVE THE INFO INTO THE DYNO COMPUTER(I ASSUME YOUR DYNO IS SAYING 160O RPM.?) wHAT KIND OF DYNO ARE YOU USING?
 

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1130cc.comaholic
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13,241 Posts
I'm not too smart :D but is there a code you could check and clear it :confused:
 

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RICK
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648 Posts
I Dont Know Who Is Doing The Dyno, But It Sounds Like He Has The Ratio Off On The Dyno. There Is A Test Ratio Button Or Icon. Set A Test Ratio At 4000rpm, The Hit The Start Button To Enter When The Bike Reaches 4000 Rpm. Then Double Check The Ratio And Rpms
 

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myvrodrocks
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Discussion Starter · #5 ·
I am no longer there, they had to close. But I am going back...

The dyno is German. I am assuming the program carries German VINs and not US VINs. The guy said when you put in the VIN is should pull all the info but it said invalid VIN.

So we did it manually. He choose Harley, then VRSCA and it came up with 2002-2003 Then the CCs were 1040 - 1140 the tire size was 170-190 17"-19" the final drive was 30/70 and the gears were like 0.20978 for first and 0.59872 for 5th and everything in between.

When I look in my book it is 10.9 for 1st and 4.5 for 5th.

We divided 72 by 30 and got 2.4 - then the 4.5 divided by the 10.9 in the book matched the 0.59872 something that was on the screen so he insisted taht was right.

I think by putting the 30/72 in, the computer should have the 10.9 and 2.4 to divide itself and come up with the .02-.05 numbers. Maybe it was coming up with half the gear ratios...

All of these numbers are approx because I did not write them down, but you get the idea.

It just did not match up...

Thanks for your assistance...I'd really like to get a reading.
 

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RICK
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648 Posts
I'm Not Sure How His Dyno Works, If It Doesn't Allow A Ratio Setting With The Bike, I Would Mess With The Numbers Until The Rpms Show Close To The Same. If You Have The Wrong Ratio, It Will Change Your Torque Figures. The Horsepower Numbers Should Remain Close To The Same. I'm Just Going By What I Know From Dyno Tuning With Our Dyno. I Could Be Wrong , Yours May Calculate Different With The Roller Program Being Used. Good Luck!!
 

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Registered
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myvrodrocks said:
hi all i am at the dyno right now and we are having some trouble.

we have all the data in the computer...but when we attempt the test, the bike says 3000 rpm and the computer says 1600

so when the bike hits the rev limiter the computer thinks we stopped a 7000 and cancels the test.


Any ideas? we have double checked the 30 tooth adn 72 tooth pulley and all the gear ratios are corret.

Please help!!
what kind of dyno is it? most dyno`s have a way to pick rpm from the primary or secondary side of the ignition coil. does this dyno have to rely on gearing calculations? in my experience using calculated rpm from gearing and tire size to be a poor way to run a dyno and really hard to get it to repeat consistently.
 

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myvrodrocks
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6,021 Posts
Discussion Starter · #8 ·
I am not sure what type of dyno it is. I do know this. The guy glued a white peice of tape to the tire. There was a laser that read the tape and counted tire RPM. Through the numbers in the system it calculated the engine RPM.

The big question that I have is this. Does anyone out there that knows dynos have a print out of the 5 gears for US model bikes? I believe the trouble is european transmissions may be different. I would like to see what your dynos are using for the 5 gears.
 

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myvrodrocks
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Discussion Starter · #10 ·
Biker Bill said:

Yes...but thast is exactly what is in my book.

the dyno guy had numbers like

1. 0.29874
2. 0.34745
3. 0.39828
4. 0.45958
5. 0.52394

He did not try the numbers in the book and I think he should have. Personally I think that was the problem.

This all would be so easy if someone out there that runs a dyno could just tell me what the 5 numbers are that they use.
 

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he must have a superflow dyno. using the optical pickup you enter the primary ratio, the gear ratio of the gear your testing in and the final drive ratio. i personally don`t like testing with calculated rpm and only do it if i can`t get a good rpm signal.
 

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myvrodrocks
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6,021 Posts
Discussion Starter · #12 ·
lbrown said:
he must have a superflow dyno. using the optical pickup you enter the primary ratio, the gear ratio of the gear your testing in and the final drive ratio. i personally don`t like testing with calculated rpm and only do it if i can`t get a good rpm signal.

Yes...exactly...but what should the 5 numbers in the gear ratio input fields be?!?!?!
 
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