I have a 03 Z400, i put a performance air kit on it and a White Bros E-series exhaust slip on. The air kit was on probably on 2 months before I installed the exhaust. when i removed the old exhaust it was really black inside the pipe, enough that you could tap the old exhaust on the floor and actually get some black residue to fall out. Does this mean it's running too rich? With the new exhaust do you think it will lean it out enough or should i make some carb adjustments. I haven't rejetted, and really don't want to tear into the carb if i don't have too yet.Eventually I want to rejet it, any advise on that would also be helpful. I'm pretty mechanically inclined, but I've had some horror stories about carbs before and am still a little intimidated.

 

My advice would be to try it with the new pipe on. You were rich before, maybe the new pipe with the increased air flow will help that problem. Also I would not be to intimidated by the carb, it's not so bad once you have to buy a new one.lol I rejetted mine in like april and broke the carb, bought another one off a buddy that put an FCR 39mm on his Z. So anyway try it out and let us know.


Chris

 

Somthing does not sound right. The Z400 has a very restrictive airbox and a very small main jet (125-130) so it is alomost impossible for you to be running too rich if you changed out the stock airfilter for a high flow filter. Now if your performance air kit was MORE restrictive then you would be too rich and thus the black soot. Any time you add a after market pipe or put a better flowing airfilter or box on a Quad you get better flow and thus a leaner burning condition.. Re-jeting is easy, the only hard part is getting the four brass screws out of the float bowl, be sure to use the right size screwdriver and don't round out the screws. I took mine out and replace them with stainless steel allen head metric bolts, makes it buch easier to change jets... I have just added a Thunder Products Dial-a-jet that is supposed to make it so you dont need to change the jet, the only issue I have now is that I am still too lean or am hitting the REV limiter because I can rev so much quicker.

03 Z400
Team Suzuki (Yoshi) slip-on
Snorkle noise baffel removed (black hood)
Thunder Products TPI (2.5" adjustable airbox vent)
Thunder Products Dial-a-Jet +1 rich, stock main jet

 

its just carbon. Dosent mean your running rich.

 

How do you like that Dial-a-Jet? Did you get it off a website? If so, what's the address?

 

Yeah you need to look at your plug, not the exhaust to tell if its rich or not.

 

Where does that carbon buildup come from?