I installed Yoshi full system on my Z400 and I changed jetting to 155. Kept stock air box with lid on. Took off snorkel. My quad has great bottom end torque but no topend. When it revs so far in each gear it starts kinda like sputtering and no power. Do I have to move the needle up or down? Do I have to adjust the air screw? Where is the air screw? I tried several different jets all the way up to a 210 nothing worked. What am I doing wrong?

btbell1323

 

Hello. Could you just be hitting the rev limiter? My son-inlaw has the tri-oval full system whith the 155 Dyno jet and the needle clip in the #2 slot. Seems to be dead on for his bike.

 

i have ran my z400 at dumont with a 150 main jet recomended from dg i have a stage 3 ecellerater head pipe and silencer but rookie me with the 400 i put the 150 in the wrong hole make sure you put it in the middle hole if the one you took out said 60 its the wrong one i have fixed that problem and it sokes the stock ones and the 400 ex baja 650 and can all most run with the yzf 450 oh sometime the airbox lid comes off and the air screw has not moved dg great pipe

 

I have a slip on w/ K&N no lid or snorkel at 5000ft. I run a 150 main and everything else I left alone..Runs perfect.

 

Reading this article may help you get the jetting right
jetting and symptoms
Sounds like its too rich on main circuit. Take the air cleaner lid off for a run( that will lean it out) if it runs better, then jet down on the main.

 

Hey, Ihave a full LRD pipe and run a 180 main. I thought it ran great until i went 3 1/2 out on the air screw and adjusted the needle. The stock needle has only one clip position but you can take it apart and move the big washer to the bottom which gives you a little more on bottom. Take the lid off and adjust the air and i think the top will be much better.