Jetting of Athena 478cc kit on YZF 2008


5 replies to this topic
  • SM-smeden

Posted February 27, 2009 - 10:34 AM

#1

Hi there..........

Just came home from 3 hours on the dyno to to jet in my bike after i mounted
a athena 478cc kit. I tried a lot of stuff: 3 different filteres, 3 exhausts,
3 nedle positions and 4 main jets. It all made only minor changes to the power
curve and nothing made substantial change to the big drop on power from
8000 to 8500 rpm.
Has anyone here seen the same thing on a Yamaha after mounting this kit?

Facts of the collurs:

Red: 145 main. Needle pos 2 up. Everything else is original
Blue: different bike with same kit. Everything else is original
Green: 145 main. Needle pos 3 up. Everything else is original
Yellow: 145 main. Needle pos 1 up. Twin pipe. Everything else is original
purple: 160 main. Needle pos 1 up. With original 450cc. Everything else is original
Black: 160 main. Needle pos 1 up. Twin pipe. Everything else is original

The big difference between the purple (450cc) and the rest (478cc), is the
drop on the power curve from 8000 to 8500. Any sugestions??? Thanks !!

Posted Image

  • ThumperKid250F

Posted February 27, 2009 - 04:26 PM

#2

very cool but by looking at your pic below your username it looks like you have a sick yz 450..

please post up some pics of that bad boy

  • SM-smeden

Posted March 03, 2009 - 01:22 PM

#3

very cool but by looking at your pic below your username it looks like you have a sick yz 450..

please post up some pics of that bad boy


Pics ??? ok
Posted Image

Still cant imgine that i am the only one who is not satisfyed with this.

Friday i will have my bike run again on a different dyno by a eksperienced
engine tuner.

I post some info if it turns out good.

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  • erickdj

Posted March 03, 2009 - 02:12 PM

#4

holy hell! is that a street bike exhaust? that's gotta be the meanest looking yz I've ever seen!

  • ThumperKid250F

Posted March 03, 2009 - 06:58 PM

#5

Pics ??? ok
Posted Image

Still cant imgine that i am the only one who is not satisfyed with this.

Friday i will have my bike run again on a different dyno by a eksperienced
engine tuner.

I post some info if it turns out good.



wow your bike is amazing..

and yes i think you still have some work to do with your motor.. im thinking maybe the bigbore just gave you low end and cut down on your peak HP

  • BlackT5

Posted March 04, 2009 - 05:39 AM

#6

Cams?





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