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Discussion Starter · #1 ·
Just got back from the dyno today. We dynoed two bikes, both had air box lid off, cam mod, jetted but one had big gun the other had gtyr full systems. Big gun made 40 horse and 26 ft pounds of torque at the rear tires with stock tires at 8 pounds. Gytr exhaust made 37 horse and 23.5 ft pounds or torque. Both bikes air fuel ratios were at a conservited 12:5 ratio.
 

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Something is wrong with that dyno.

Just goes to show you that you can't race dynos. :lol
 

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What tires did you guys run? Whether or not the dyno is way off or a little at least you can use it as a tool for back to back testing. It seems that everyone is going with the highest reading on the net and making that the baseline. How do we know that is not wrong? I posted my results way back. Street tires, 15 front sproket, cam mod, K&N, no lid, jetting, and heavy modded stock muffler. The computer was unable to give torque. Just a hp curve and peak with mph. Mine was 44 peak. Other YFZ's were dynoed on the same one with sparks and tc pipes but with nobbies. 15% seems to be a close rule of thumb for what I hear and read for HP differences from the two tires. On nobs they made 34 to 36. Take 15% from mine and you get 37.4. I plan on making more changes and tests on my quest for 55hp. We will see.
 

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Originally posted by bansheekiller@Jan 2 2004, 01:33 PM
Big gun made 40 horse and 26 ft pounds of torque at the rear tires with stock tires at 8 pounds.
I think he had stock tires on. But I dunno.



And yeah the dyno tires will show higher numbers. But some have dynoed with nobbies and made over 45hp.

The point is yoiu can't dyno race. Only use dynos for tuning.
 

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Discussion Starter · #6 ·
Yes we did have stock tires on both bikes with 8 pounds of air. Evey dyno reads different and some read more than others. For example I race a turbo gsxr 1000. On a plain old dyno jet dyno the thing made 285 horse at the tire with 20 pounds of boost. Same bike on a New dyno jet dyno with tunning link tunning the bike with the power commander and being able to see the air fuel at every rpm it made 268. You can easly change the numbers from actual horse power to the din setting and make it look like the bike made more. If you honestly think these two bikes make less power than a stocker than I'd love to race ya. :D
 

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does any1 know what hmf stats are? and what does stock actually say
 

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Discussion Starter · #8 ·
Parhump your exactly right. The only reason we dynoed these bikes was to make sure the air fuel ratio was in the safe zone and you can't race a dyno. Mine made 40 on this dyno but might make 45 or even more on another. Either way when I ride now I know mines tuned. I knew when I made this post people would think those numbers are low.
 

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Discussion Starter · #9 ·
Before I forget. A totaly bone stock 450 on this dyno makes right at 30 horse at the tire. 8|
 

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Blacktopr, what did you do to your stock pipe?

do you fell it is comparable with the aftermarkets?

Bansheekiller, that is good info on the 10 hp gain from your mods, no matter how low or hig the numbers are.
 

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I don't know how I missed the stock tire, Pahrump, thanks for catching me. :eek BigAl, for a slip on, yes I do and there are others on this site that believe it too. Mine has more than the hole in the back of the pipe. I cut the thing in two places, opened it up and cleared out more area then welded it back. It still sounds like any stock muffler without the peashooter. And it took a full TT lightweight quad to get me by 2, on the street, for 300 ft. A full run in the sand would have been a different story.
 

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I done the same to mine blaktopr, but I did not cut mine I just drilled it out. I don't know how much it helped with performance but you can really feel the exhaust coming out now.
 
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