Hey everyone just need a little help with my jetting on my 03 Z400 I just got a full exhaust by bill's pipes and i am getting a k&n filter and was just wondering what size jets i should put in ? and i was thinking of a cdi box and what you all think of them if you have used them, and is it worth it ?they give 1000 rpm more so would i have to jet it different for that to ? thanks

 

does any one have an idea?

 

Start with 25 pilot, 3 turns out, Alba needle at the 4th clip from the top, and a 155 mikuni (NOT dynojet) main. Should be close to perfect, possibly a tad rich.

 

I would buy the DYNOJET kit stage 1 & 2. The instructions give different setups for whatever you have done to your machine or at whatever altitude.........

 

Don't waste your time with a Dynojet kit...I did, and ended up not being worth the $$$ besides the needle. BVSTONES jetting specs look right on.

13inc...nice bike by the way

 

Thats sounds like some complicated jetting.I'm glad all I had to do was change out my main jet.HMF recamended a 175 and its perfect.

 

It's not complicated at all. 175 is WAY too fat for the main.

 

I don't know what elevation you guys are at but a 155 sounds lean to me. I live in southern AZ around 2900ft for elevation and I have done the prodesign pro-flow filter with no lid and I,m running a 150 mj. When I det a pipe later this year I not sure what mj I'll have to use but I imagine it will be a 160 or 165.

 

No, most people run a way fatter main than they need... on the Z, you should never need to go over 160.. Even with my 42mm carb I'm running a 155 and I gather it's a little fat.

If you were running too lean, you'd know before causing damage. People are still paranoid about running too lean from the 2 stroke days.

 

BV's right again. Many people think that the higher main jet you slap in the more power you will get...which is all wrong. I also think that a 175 is too large for a pipe only...try going down a couple sizes and see what that does for ya, and if it doesnt work...than go back to the old. Can't hurt to try!