I've heard alot of talk about crank case filters on the raptor when removing the airbox lid. On my warrior the crank case vent hose goes up to the snorkel but does not have any type of filter. Should there be a filter on this hose? The way it's set up from the factory the hose connects to the snorkel before the air is filtered, does this sound right?

 

You have the same set-up as the Raptor, no filter in the hose either. The crankcase vent hose PUSHES air (so no filter is necessary)...no suction. No one has ever given a circumstance where the hose would actually suck dirt/debris.

 

If that's the case then why do people put an aftermarket filter on it when they mod the airbox?

 

The reason guys put filters on theirs is they read/hear horror stories about engines with sand / dirt in their engine.

Instead of looking at the pathetic stock air filter set-up, they assume crankcase vent hose must have let the debris in. These "TYPE" of posts went away when the aftermarket had intake kits available (pro design, sparks, etc..) to get rid of the pathetic stock set-up. These are my assumptions......if anyone has PROOF that this actually happens, feel free to speak up.

 

well ill speak up! if the the crank didn't suck air why do the companies make crank filters? also nobody knows wheather or not it has a vacume, but for 13 bucks ill play
it safe! also look at a car motor they have vent and crank hoses all over and they all have a filter on them.

01 blu 660r

 

The reason I installed one is simple: after altering my airbox lid, the hose has no place on the airbox to connect into, leaving it lying unprotected behind the gas tank and vunerable to a blast of sand or mud. Since the "fume" output volume of this hose is small, foreign material under reverse pressure could enter it and foul the crankcase. The cheap filter insures this can't happen. An ounce of prevention is still worth a pound of cure.

 

I agree it's best to be safe than sorry. This is why I ran a crank case filter for a long time.

I rev mine up and it is pushing air......I let off the gas and rpm's come back down and it's still pushing air. I can't see why the filte r is necessary???? My intentions are not to get anyone riled up[img]i/expressions/face-icon-small-happy.gif[/img]. I would like to find some type of definate answer........

 

sorry I wasn't clear enuf. If a hi pressure stream of sand, mud, dirt, etc comes off the front or rear tire and hits the unprotected end of that hose, the crud will make it down that tube and into the crankcase. Is it likely? NO. But a $2.00 part makes it impossible, so why chance it?

Just call me a fraidy-cat.

 

I agree with the cheap insurance. For a couple of bucks, you can get a crankcase filter that is really designed for a car. They come in various sizes so I just found one that fit the Raptor hose.

I wonder if you put the hose in a glass of water if you would find that it does more than just blow bubbles. At idle, I could swear that mine sucks air and then blows air back and forth as the piston goes up and down.

The reason I think it is on the intake side is to help burn off any gases that slip by the piston rings down into the engine. It is an emissions thing with cars that might apply to quads too.