One of my friends wants me to ask everyone what would happen if he ran his 400 sport without the airbox!? he said that when he took it off it FLEWWW but he wants to know whether it will do any harm or not. thanx cya

 

yes go for it,remove this poor airbox and replace it by a k&n
filtercharger,get instant torque and hp gains,but don't forget to ckeck the spark plug color and jets after installation and keep an eye on it when riding into muds,i run kick *** air filter (for snowmobile)into mine scrambler and they're better,more air as well.

 

Yeah, flowing a lot of air on the stock jets may cause a lean problem. I remember hearing that Polaris jets a little rich, but I don't now how much. He'll deffinatly want to check the plug.

Also, if he's in really wet and muddy conditions I don't know how well that setup would protect stuff from getting in.

-Josh

 

Until he upgrades to a larger carb I don't think it will make a huge improvement. It will help a tad, but beware of the riding conditions in which you ride as the box is there for a reason. I haven't used mine for over 2 years, and run an open K&N off my 39PWK.

 

yes that right,if you have the stock carb doesn't worth it anymore,
the no-airbox mod is better for bigger carb as well.