k i have a Z400 with no air box lid, ct full pipe ( no spark arrestor ). k&n filter, dyno jet kit with needle on third clip, 155 main ( biggest they have ) and a 25 pilot. im having some problems.

the bike seems to run fine but when i rev it up it sounds like its hesitating about 3/4 maybe or maybe a little after 1/2. when i stab the throttle real fast it will just die, or after i rev it up fast by holdint it open after i let off it will die?. it shouldnt do that should it?. i dont know whats wrong. also when im riding if im climbing a hill and hold it wide open then have to stop or slow down i pull in the clutch it will die also some time going down hill with the clutch in it will also.

i replaced my spark plug and the electrode was barley brown but it was real black all over everywhere else. it seems like im running rich. am i too rich on the midrange?? also when i put the airbox lid on i wont even go anywhere it burps and dies after i start to open it up.

thanks for the help

 

when this happened to me i noticed that my choke was slightly closed (i must have accidentally hit it). after this incident, i have heard of someone say that the choke on theirs was misadjusted and it caused the same problem that i had. well, to make my answer short, make sure that your choke is fully open (check in the carb not on the lever). btw, 155 sounds abit small. you might wanna try a couple of sizes larger.

 

im using the dynojet 155 which is the biggest there is.

 

I dont know if this will help but I got mine from Trinity with no lid and the alba k&n filter kit and run a 165.