TOPIC:

Wow, lot of replies since I got to work!!!

@swest, you are right, my tube goes to the airbox (I have the original).

OK so from the comments I see this does the same thing as the vent in the valve covers on my old V8 engine. Makes more sense now. @Patton, one thing that comes to mind... wouldn't there still be some oil blown up the tube to the airbox? Seems like some kind of filter in the line would be better than filling the airbox with oil, but since I don't see any sign of oil in my airbox I assume that doesn't happen in practice. So in that case, what is the difference between venting the gasses into the airbox or having a small filter sitting directly on top of the cover? Seems like they would both be just as functional?

Patton wrote: Am not a fan of attaching a filter on the crankcase breather or on the end of the breather tube.

Imo, the filter contributes nothing, and gets progressively clogged with oil, which diminishes breathing ability of the crankcase.

Oh Wait! The filter might prevent oil-eating alien beings from entering the crankcase.

And when feeling the inexplicable need to filter out-coming whatever from the engine, should definitely also add a filter to the end of each muffler.

Filters may also be added to the ends of handlebar grips, and to the ends of foot-pegs, and to the ends of valve stems to assure that any old unclean air that escapes from inside the handlebars or foot-pegs or from inside the tire through a leaking valve stem will be squeaky clean before entering the atmosphere.

Good Fortune!

Three guess's on who gave me the reamin on the crankcase filter. .....but thats cool.... when it comes from a guy that has forgot more about motorcycles that I'll probably ever know I can take it.

Shdwdrgn wrote: ............. Seems like some kind of filter in the line would be better than filling the airbox with oil, but since I don't see any sign of oil in my airbox I assume that doesn't happen in practice. So in that case, what is the difference between venting the gasses into the airbox or having a small filter sitting directly on top of the cover? Seems like they would both be just as functional?

On my BSA Cyclone engine the crankcase vented through a tube that directed the oil mist directly onto the drive chain near the engine sprocket. Ed

My 350 Honda was that way too. If there is so much blow by, the engine needs to be repaired anyway. Hate to see what the bores look like in that clip.
Steve

650ed wrote:

Shdwdrgn wrote: ............. Seems like some kind of filter in the line would be better than filling the airbox with oil, but since I don't see any sign of oil in my airbox I assume that doesn't happen in practice. So in that case, what is the difference between venting the gasses into the airbox or having a small filter sitting directly on top of the cover? Seems like they would both be just as functional?

On my BSA Cyclone engine the crankcase vented through a tube that directed the oil mist directly onto the drive chain near the engine sprocket. Ed

Is the purpose of a vent-hose to the air box for the crankcase fumes to get burned in the combustion chamber?
Seems to me that oil could contribute to fouling spark plugs, since it is essentially being continually sucked from the motor by the piston intake stroke
I like that little filter, if only for my bike having a drive shaft.

That's the idea. It also removes heat from the crankcase. If there is too much, the engine needs work.
Steve

Good Fortune!

Filters like the K&N's on the end of the crankcase breather are meant to keep dirt and water (as in car wash or heavy rain) from entering or being sucked into the crankcase. The pistons act like pumps on both sides, alternating between pressurizing and creating vacuum pulses in the crankcase. The breather keeps these pressure pulses from blowing seals and causing excessive oil consumption. A pressure of only 1 or 2 psi can blow a countershaft seal, so the crankcase must be well ventilated to prevent this. With the stock set up, for emissions, the vented oil mist / fumes are routed into the intake to be burned in the combustion chamber, just like PCV systems that where introduced on cars in the sixties when vehicle emissions became a serious concern. Burned hydrocarbons are considered to be less harmful to the environment than solid / liquid fuel and oil or unburned hydrocarbons....

K&N says the crankcase vent filters are designed for the high demands of racing. [Snicker-snicker-wink-wink]. Without further ado 'bout those high demands. And neglect to mention any professionals using them. But do take the time to also plug sale of K&N's filter cleaner and special red oil essential toward maintaining the filters.


Other options for an open nonrestrictive breather hose would be routing it to exit underneath or behind the bike.








Good Fortune!

Patton wrote: K&N says the crankcase vent filters are designed for the high demands of racing. [Snicker-snicker-wink-wink]. Without further ado 'bout those high demands. And neglect to mention any professionals using them. But do take the time to also plug sale of K&N's filter cleaner and special red oil essential toward maintaining the filters.


Other options for an open nonrestrictive breather hose would be routing it to exit underneath or behind the bike.

Good Fortune!

Hey, don't bring old Meriden Triumphs into this filter "engineering" topic - hell, they didn't even put oil filters on their bikes back then.... (Don't get me wrong - I would pay big bucks for a nice stock 650 / 750 Bonneville).

I think K&N would use that statement on everything they sell - all hype and glitter. In the end, I believe the description was meant to refer to the free breathing ability of their crank case filter, in that it would not restrict crank case ventilation and cause seal failures or excessive oil consumption. even under racing conditions. And nothing is as demanding on a machine as racing....