Jetting of Athena 478cc kit on YZF 2008

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 !!

478testhelside.jpg

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

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

03032009319.jpg

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.

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

Pics ??? ok

03032009319.jpg

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

Cams?

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