Doughansing, you will definitely have to rejet your carb when you install your exhaust with the airbox lid removed. I believe the stock main jet is either a #125 or #130 stock. We bought our Z from Vesco's last year. We installed a Pro Flow kit with a K&N filter and a full HMF pipe. I settled on a #148 to #152 main depending on the season. We eventually installed a jet kit with the adjustable needle to dial in the midrange. After all that, we sold the Z recently and purchased a used Yoshimura Z450 with an Edelbrock carb. Man, it runs good!

 

Buddah...

How does your Yoshi 450 compare to your YFZ?? I have raced a Yoshi 450 once and I agree they aren't a joke!

 

It runs strong. The power is very broad and smooth. It doesn't hit hard like the YFZ. The power is very deceiving compared to the YFZ. I haven't dragged them side by side yet, but I think it will be close. The Z is definitely less tiring to ride, there is no comparison there. The bottom to mid is where most of the power is. I'm running an Edelbrock carb, E series pipe, with a Big Gun rev box. I would like to try some different combos to see if there's a difference. I'm very happy with the power it makes. My wife's other Z had a full HMF pipe, jet kit, Pro Flow, and Hotcams and it ran good. However, it doesn't compare to the Yoshi 450, especially in the bottom end and midrange.
I'm very happy with it. In fact I might keep it for myself, sell my YFZ, and buy the wife another Z. Haven't got that far yet. Hope this helps

 

Yeah thanks I was just curious. I saw your YFZ on another site and it looks like its a runner. What combos do you mean...different pipe, ignition, or carb maybe??

 

Yes. I would like to try a programmable ignition and a different pipe at sometime.

 

Go with the Yoshi you won't be dissapointed !!!

 

hmf is giving me a 170.

 

If you go to hmfengineering.com. It recomends the right size jets for where they ride. You could start there and then fine tune it. Iam currently running a 175 main but can't remember the needle positioning.

 

03:
Is it in the HMF engineering forum you found the site specific jetting information?
thanks, Doug