For those of you that havent dont it:

Screws on the carb bowl suck....had to chisel them off
I used a 165 jet...with air box off...didnt run right. I should have used the 162.5 jet

With the air box on the Z400 screams...it is awesome.

Does the airbox off(and K&N) make that much difference?

I right in harsh trails...lots of mud,water and dirt. So I think I will keep my airbox lid on. Or is there so much power difference it is worth it?

If you havent dont it...the power from the pipe is amazing. Give it gas and the front end lifts up like nothing!

Steve

 

The more air you can get into and out of your motor, and the faster you can do it, the more power it'll make. Go muddin' and see where the cleanest part of the airbox is on the outside. Then drill some 1-inch holes and get the foam vents to put it them. That'll let more air inand help keep your filter clean. And you'll probably need to re-jet again.

 

I ran my airbox lid with no snorkle over the winter. This spring I pulled the lid off and it made a huge gain (felt like about 1/4 throttle power increase).