The crank case vent does just that. It ventilates the crankcase. When the motor is initially started the air in the crankcase is at ambient temperature. As the motor heats up the air within the motor expands thus requiring ventilation to atmosphere. If the motor is not vented pressure will gradually build and can potentially blow your engine oil seals. So it will self ventilate (not good). The crank case vent works in the reverse when the engine cools. As the engine cools it draws in outside air and if not filtered it will also draw in dust or water if tube happens to be submerged in it. This is especially true when stalling the motor in water because you take a hot motor then cool it quickly causing the vent tube to vacuum up water into your crank case (also not good). The crank case vent also allows for pressure fluctuations due to piston movement and thus the air pulse you notice while the engine is running. It also allows for compression blow by and volatile fumes to escape. On many vehicles the crank vent tube is down stream of the main air filter thus filtering any incoming air. Other setups usually have an independent filter directly on the crank case vent. Either way it is a good idea to have a filter. Just make sure it can handle the air volume required to properly ventilate the motor under all conditions or your bound to have an oil leak. Oh yea and make sure you clean it now and then too. Sorry for the long winded explanation didn’t want to be criticized for leaving any thing out although I’m sure I might have. Good luck.

 

This is what a Raptor is all about!!
2001 Blue Raptor
Over 30 Hours of riding time on it plus a 30 mile
H/S race 1st place and love it!!

97 Banshee (GONE!)

Mods on raptor to date.
Airbox
Twist throtle
Axis front shocks
Clutch lever & ebrake blockoff
ITP Racing wheels
Tires:Shredders rear & Bandits front

 

Hey Trickraptor, where did you get your twist-throttle kit? I want a CR type throttle, not the piece of crap whirlpool type. Let me know who sells these. (with the appropriate cable)

 

Whats the last 4 numbers on the serial number?
I wonder if it was made before or after mine...

 

WHAT ABOUT RAPID DECELERATION (GEARING DOWN WHIT THROTTLE CLOSED) THIS PUTS THE PISTON IN A VACUUM,INSTEAD OF IN A HIGH PRESSURE BLOW BY SITUATION? WOULD THIS PUT THE CRANKCASE IN A POSITION TO SUCK IN DIRT AT THE TIME WHEN THE BIKE IS ENGULFED IN DIRT? I DONT KNOW.

 

Twist throttle is made by Motion pro for a Warrior
but you have to shorten the inner cable.
Which is no prob
Just cut the inner cable to the right size and use a lead bullet fishing weight.
Melt the weight on the cable with a good hot soldering iron then shape the weight into a ball.
It took me about 30 to 40 min to do this

 

No, closed throttle deceleration would make no difference on the crankcase pressure. As long as your rings are good, you would never have enough vacuum to supply the cylinder with air via the crankcase side (in a 4 stroke). If it did, you would have lots of oil smoke, because it would be sucking oil up into the cylinder as well.

We might as well give up on the breather theory, under normal circumstances, there is no way that it would suck up enough dirt/sand to cause a problem.

If you've ever looked at an older carbureted truck, the valve cover gaskets often have a hose running to the air cleaner. It is the same type of method used with the Raptor to vent the crank case and at the same time, recycle the fumes/oil mist back through the combustion process. Many of the truck set-ups were prior to the filter, just like the Raptor is.

 

OK.HOW DID THE TUBE GET COATED WITH A THICK LAYER OF DUST AND DIRT. PURE F***ING MAGIC?

 

just take a pice of material like a piece of nylon pantyhose and stretch over the tube then plug it back into the intake, end of story. then thank your grandma.

 

Grandmaaas pantyhose,ewwwwwwwwww. You couldnt of thought of another place to get some from.I thought our goal here is to keep dust out of the motor,NOT IN IT!!!!!