well i got some of those white brothers air vints no i did not jet it but i did't thank that would mater so if any one can help i would appreciate it i want to put just a slip on and jet it do you guys thank that would do

 

if your gonna be getting a slip on soon. you may want to just wait to rejet and put some tape over the vents you installed.

 

I also have a z400 and sometimes it backfires for nop apparent reason not sure i have it all stock jetting is important though pretty much everything you do to it requires it to be rejetted even the temp changes and humidity effect which jet would work best

 

thanx im not going to put a k&N air fillter on cuz some peps said that the stock one was just as good and keep more dirt out of the moter but do u thank the holes will be good when the slip on and jet it

 

thanx jonzo

 

you have to rejet if you change the air flow into the carb. The vents are putting more air to fuel and its running lean. I dont know where you learned that the stock filter filters better than a k&n, that must be why almost every pro rider used the k&n. That is false, k&n flow better, yet block more dirt from entering.

 

when i put thoughts vents in i fill air come out not suck in

 

All the pros use them becasue they let more air in. They dont stop the junk better, if anything its worse. The pros do it for perfmormance. I dont want to fight or anything, thats just what I think.

 

yeah same here when and if i start racing i will git one good pont z250freak

 

Like most bikes/ATVs the OEM set up are dead on/ to a bit lean for epa regulations. If you increase the air flow into the air box you will be lean and get back fires.