Ask The Editors: What Is A Valve Separator And Do I Need One?
Does this do anything? The answer may surprise you.
Our first thought, as seeing how many manufacturers run these things on road-going motorcycles to serve as anti-emissions measures (by injecting a certain percentage of clean air from the air filter into the exhaust manifold to help burn and dilute hydrocarbons that escaped the combustion chamber prior to being sent down the pipe) was that ditching it would be the wise move.
However, after doing more research, it seems as though there are other purposes for such a device in the off-road arena. According to Kawasaki’s own documentation, the valve separator serves as a sort of engine pressure relief valve. It monitors internal engine vacuum levels then opens and closes to divert the flow of crankcase vapor. Hints of what the device is doing are right there in its name – it’s a separation valve that determines what to do with internal vapors being created inside your engine’s crankcase.
When the engine is under load (think when you get on the throttle hard, tow or climb), it redirects vapor into the intake manifold – basically giving the engine more air for the process of combustion under strain.
When the engine is at rest (like at idle or when decelerating) it alleviates crankcase pressure by sending that pressure out into the atmosphere.
All of this to say, yes, such a device would absolutely be affecting the machine’s performance all the way across the board if it’s malfunctioning or broken.
The entire assembly consists of two parts – we’re enclosing the diagram with the OEM part numbers for you below. And searching salvage yards, eBay and the like does turn up several used units if spending OEM cash is a bit out of your budget.
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