Post by Dandy Dan on Nov 15, 2008 13:14:39 GMT -5
WARNING: Tech Geek Content
Background:
The engine case ventilation in the 2003 - 2005 Ruckus's was simply one hose going from the engine to the airbox. Any engine 'breathes' because the volume inside the engine case is changing as the piston pumps up and down. The system in these early Ruckus's didn't work very good because the engine was trying to exhale and inhale through the same hose....just like how a snorkel doesn't work for a person if it's too long. The result of this poor ventilation was diminished oil life and eventual failure of the crankshaft bearings.
For 2006, Honda improved the ventilation system by adding a second hose, which had a one way valve. Since this hose had a one way valve, air can enter into the engine but it can't exit.
Question:
Currently when a Ruckus's engine inhales, it breathes in through both hoses because the exit hose does not have a one way valve, so dirty air is free to flow back into the engine as it sucks in. So each 'breath' is actually half fresh air (via the new hose) and half old air (sucked back in from the exit hose). When the engine exhales, it can only exhale through the exit hose because the fresh air hose has the one way valve. The net result is that the engine is only cycling half as much air as it could, because it's only breathing in half a breath of fresh air. Still with me? So my idea is what if we put a one way valve in the exit hose too? So now the engine would half to inhale a full breath of fresh air and exit a full breath of dirty air. The result would be twice the air flowing through the engine.
What I'm wondering is if this would actually be an improvement? Or is the current ventilation system already cycling more than enough air?
Background:
The engine case ventilation in the 2003 - 2005 Ruckus's was simply one hose going from the engine to the airbox. Any engine 'breathes' because the volume inside the engine case is changing as the piston pumps up and down. The system in these early Ruckus's didn't work very good because the engine was trying to exhale and inhale through the same hose....just like how a snorkel doesn't work for a person if it's too long. The result of this poor ventilation was diminished oil life and eventual failure of the crankshaft bearings.
For 2006, Honda improved the ventilation system by adding a second hose, which had a one way valve. Since this hose had a one way valve, air can enter into the engine but it can't exit.
Question:
Currently when a Ruckus's engine inhales, it breathes in through both hoses because the exit hose does not have a one way valve, so dirty air is free to flow back into the engine as it sucks in. So each 'breath' is actually half fresh air (via the new hose) and half old air (sucked back in from the exit hose). When the engine exhales, it can only exhale through the exit hose because the fresh air hose has the one way valve. The net result is that the engine is only cycling half as much air as it could, because it's only breathing in half a breath of fresh air. Still with me? So my idea is what if we put a one way valve in the exit hose too? So now the engine would half to inhale a full breath of fresh air and exit a full breath of dirty air. The result would be twice the air flowing through the engine.
What I'm wondering is if this would actually be an improvement? Or is the current ventilation system already cycling more than enough air?
You are missing the point. When an engine is cold, the piston rings have not expanded so they are not doing a great job at sealing, a lot of the gases expanding during the combustion stroke find their way around the rings into the crankcase, increasing the pressure inside the crankcase, if this pressure is not allow to vent, oil will start blowing under the gaskets and create all kind of problems, so this hot air under normal conditions will go to the highest point of the engine, where you can usually install a hose and get them back into the combustion chamber to be burn, instead of just into the atmosphere like old cars used to do. Once the engine warms up the rings expand and the blow-by stops (hopefully), the early ruckus uses a restriction on the airway going into the intake track as a one way valve but does not provide fresh air, so it relays only on the suction from the intake.Now the piston moving up and down creates pulses, you can use these pulses to move fresh air into the crankcase and blow the remaining gases into the intake ([glow=red,2,300]P[/glow]ositive [glow=red,2,300]C[/glow]rancase [glow=red,2,300]V[/glow]entilation) or PCV for short, so later models use a fresh air supply with an electronic valve to only supply fresh air to a warm engine, and it seems to work wonderful ;D 
The volume of air going thru the vent hose is so little (there is a restrictor in it) it does not make much of an impact