very stupid question

[fox17]

i feel stupid asking this but what is the crankcase breather tube? is it the tube that is inside the airbox that sits close to the filter? i want to get a filter for it but dont know where it is??? i dont have a box lid on so i figure if that is it i NEED one.

[Mx_523]

Originally posted by fox17
i feel stupid asking this but what is the crankcase breather tube? is it the tube that is inside the airbox that sits close to the filter? i want to get a filter for it but dont know where it is??? i dont have a box lid on so i figure if that is it i NEED one.
"what is the crankcase breather tube?"
It is a tube that lets your crankcase let out hot air and lets it cool down.

"is it the tube that is inside the airbox that sits close to the filter?"
No, you might be thinking about the hole that drains water out of the air box.

"i want to get a filter for it but dont know where it is?"
On my 300ex, it is located infront of the engine on the left side, on the vertical frame rail.

"i dont have a box lid on so i figure if that is it i NEED one"
As long as your not letting dust and such though your filter and into the intake you should be fine.

Hope this helps, I'm not sure if its all correct because my 300ex is two years older than your 300ex and they migh of done something else to it.

[fox17]

thanx. ill look at it tomorrow. i have no idea where it is???

[Mx_523]

No problem, but like I said, the things I stated are on my 300ex. I'm not fully 100 percent sure how they are on your's considering your's a 2000. Anywho, it should be a black tube about a 1/2" in diamiter.

[bwamos]

The breather tube comes out of the top of the Cylinder Head. On the 1987-1999 300ex's it come out and goes up the right side frame rail and terminates up near the steering stem. On 2000+ models it goes backwards along the left frame rail into a smog box (translucent plastic box made to catch any oil), and then into the airbox so it will recirculate into the engine.

What the crankcase breather does is allow air to enter and escape the crankcase as the piston moves up and down. Keeps the piston from having to compress the crankcase air as it travels down.

The tube you are seeing next to the air filter is the crankcase breather.

Since you are running no-lid on the air box.. You could rip off the breather tube and the smog box (since it's doing nothing but giving you a straw to suck up water without the airbox lid on).. and replace it with a breather tube from a 1998 or older 300ex.

Or you could put a breather filter on the airbox as you suggested. K&N has universal filters you can use. If there's a flange on the airbox you can use to mount a filter you're set. If not it could be tricky.

K&N Breather Filters (http://www.knfilters.com/vent.htm)

You could probably even just mount a rubber flanged filter onto the brass breather tube coming out of the head of the engine and completely get rid of the tube.

The one at the bottom of the page with the shield would probably work well (if there's room).

[fox17]

ok. thankyou. that helps a lot.