Just got my wife an 05 Z400. It was running fine until I installed a DG header and silencer, removed the air box lid and snorkel and added a new dyno jet Kit that was supposedlly updated by dynojet for the changes Suzuki made to the new bike. The bike is really lean on the bottom for the first 1/4 throttle, then cleans up fine even though I'm having to run a 170 to get it to take the gas on the top end. Dyno jet reccomends a 150 for my set up with their needle with the clip on the 3rd notch, and mixture screw out 3.5 turns. It wouldn't even run with out poping and spitting fire with that set up. (They have yet to respond to my email to their trouble shooting department). There are no vaccume leaks, I have checked all the intake 100 times, the filter is secure, I even reinstalled the air cleaner lid, taped off half of the snorKle hole and it was still lean on the bottem to the point were if you were ridding and let of the throttle less than 1/8 or so it would die and fall right on its face. There is 3 jets in the carb. I replaced today (what I thought was the primary/idle jet) with a 82.5 and now it revs up like I',ve pushed the throttle when I start it. I even backed the idle adjustment screw all the way out. The only jet left is a #20 something which I will try to replace in the next day or so, and get rid of the 82 I put in today. My TRX450R was a slam dunk to tune but this damn vaccume slide carb is killing me! Any tecnical help that is 1/2 way educated would be more than appreciated!!! Thank you[img]i/expressions/face-icon-small-disgusted.gif[/img]

 

hmmm i just ran a dyno jet 165 in mine with stock needle white bros power filter with 2 2inch holes in lid ran great and we are at 1174 feet

 

Thanks for the post, but yours is an 04, (different carb, and cam) and we are running at sea level so the altitude would make yours a little fatter, Plus your box lid is still on. Interseting though that your main jet is a 165, thats pretty good size with what your running, is that what white bros reccomended?

 

thats what hmf said to use

 

if its lean on bottom try to up the pilot jet the should be the 22.5 stock

 

I know you said that there are no leaks but check to make sure there isn't an exhaust leak at the head, sounds like you may be sucking in some air possibly. Does it idle ok? If it does I would try raising the needle and take the mixture screw down to about 2 1/2 to 3 turns out.

 

i would check the intake, it does sound like an air-leek. if not, go up a notch on the needle and up a size on the piolit.

 

installed a new #30 pilot jet today, and reduced the main to a 165. Much, much better, no more leanning out on the bottom and finally a normal idel. I might fatten the bottom just a bit more and back the top off another step. Thank everyone for their feedback, but it was the pilot jet after all.[img]i/expressions/face-icon-small-wink.gif[/img]