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Discussion Starter #1 (Edited)
So, I recently purchased a 97 800A and the previous owner installed a hyper charger. There is an issue cruising at 70, but I'll save that for another thread after I try some of the fixes I ran across here.

My question is about the EGR valve. It looks like most of the hoses were removed completely, and the openings were not sealed. Would this cause any issues down the road? I will be removing it today after purchasing some vacuum caps, just wondering if I should be wary about any junk due to it being open.
 

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As long as the nipples on the valve covers are blocked off, and there are no open ports on the air filter, you should be ok. On the vale covers, a single piece ohf hose between them is ok, as long as they are not drawing in outside air.
 

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As long as the nipples on the valve covers are blocked off, and there are no open ports on the air filter, you should be ok. On the vale covers, a single piece ohf hose between them is ok, as long as they are not drawing in outside air.
I ended up taking the entire thing off, hoses included, and put some vacuum caps on the valve covers and the exposed connection on the petcock vacuum line.
 

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This isn't an EGR valve. It's an Vacuum Switch Valve that works in conjunction with the Air Suction Valves located in the top of the cylinder heads. Both are there to properly vent the crankcase. The air suction valves allow crankcase fumes to escape out the exhaust passages built into the cylinder heads into the exhaust system. The Vacuum Switch Valve allows filter air from the air cleaner to enter the crankcase.
If you want to remove the VSV you have to vent the crankcase to the atmosphere with some kind of filter on the end of the crankcase vent hose and I would recommend running a hose between the two valve covers to help in equalizing internal air flow.
 

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This isn't an EGR valve. It's an Vacuum Switch Valve that works in conjunction with the Air Suction Valves located in the top of the cylinder heads. Both are there to properly vent the crankcase. The air suction valves allow crankcase fumes to escape out the exhaust passages built into the cylinder heads into the exhaust system. The Vacuum Switch Valve allows filter air from the air cleaner to enter the crankcase.
If you want to remove the VSV you have to vent the crankcase to the atmosphere with some kind of filter on the end of the crankcase vent hose and I would recommend running a hose between the two valve covers to help in equalizing internal air flow.
This is pretty much what I did minus capping the air cleaner, since that does not exist on the hyper-charger that was installed by the previous owner:

https://www.youtube.com/watch?v=c73kzvWUfio
 

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Kawasaki VN800A (1995). Yamaha Raider (2008). Yamaha FZ1 (2006).
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This isn't an EGR valve. It's an Vacuum Switch Valve that works in conjunction with the Air Suction Valves located in the top of the cylinder heads. Both are there to properly vent the crankcase. The air suction valves allow crankcase fumes to escape out the exhaust passages built into the cylinder heads into the exhaust system. The Vacuum Switch Valve allows filter air from the air cleaner to enter the crankcase.
If you want to remove the VSV you have to vent the crankcase to the atmosphere with some kind of filter on the end of the crankcase vent hose and I would recommend running a hose between the two valve covers to help in equalizing internal air flow.
My understanding was that air suction valves allows not burned gases & fumes from the head, to go through vacuum switch valve, back to airbox and so in cylinder again..
I appologise if I'm wrong, don't want to spread NOK info, but need to understand.
If you remove only the VSV, the crankcase hose (the hose connected only to the rear cylinder)) could remain connected to the air box, no realy need to vent it separately with an additional filter.

or ?
 

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My understanding was that air suction valves allows not burned gases & fumes from the head, to go through vacuum switch valve, back to airbox and so in cylinder again..
I appologise if I'm wrong, don't want to spread NOK info, but need to understand.
If you remove only the VSV, the crankcase hose (the hose connected only to the rear cylinder)) could remain connected to the air box, no realy need to vent it separately with an additional filter.

or ?
Hi Marcelm,
I also need to understand this as it has never been explained to me in detail so I am left to try and figure it out for myself. So don't take what I say as gospel (being true). I will give you my understanding whether it's right or wrong maybe someone else can say.
The air suction valves are a one way reed valve which allows air flow in the direction of the exhaust port, not into the top of the cylinder head. When exhaust gas is flowing out of the engine the pressure at the head is lower then atmospheric pressure causing air to been pulled out of the engine into the exhaust pipe. The primary reason for this is to supply extra oxygen to the hot exhaust gasses to allow more complete burning and therefore lower emissions of unburnt gasses. And then secondly help remove crankcase emissions. The Vacuum Switch Valve's air flow is from the air cleaner box to the tops of the valve covers. This valve is closed when the engine is under high vacuum like when idling or de-accelerating. When the engine or bike is running at medium to high speeds the vacuum is not strong enough to overcome the spring pressure of the valve and it opens and air from the air box flows through the vsv and into the tops of the valve covers and then out the reed valves into the exhaust for more complete combustion.
That's the way I think it works, again I could be wrong.
 

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Hi Marcelm,
I also need to understand this as it has never been explained to me in detail so I am left to try and figure it out for myself. So don't take what I say as gospel (being true). I will give you my understanding whether it's right or wrong maybe someone else can say.
The air suction valves are a one way reed valve which allows air flow in the direction of the exhaust port, not into the top of the cylinder head. When exhaust gas is flowing out of the engine the pressure at the head is lower then atmospheric pressure causing air to been pulled out of the engine into the exhaust pipe. The primary reason for this is to supply extra oxygen to the hot exhaust gasses to allow more complete burning and therefore lower emissions of unburnt gasses. And then secondly help remove crankcase emissions. The Vacuum Switch Valve's air flow is from the air cleaner box to the tops of the valve covers. This valve is closed when the engine is under high vacuum like when idling or de-accelerating. When the engine or bike is running at medium to high speeds the vacuum is not strong enough to overcome the spring pressure of the valve and it opens and air from the air box flows through the vsv and into the tops of the valve covers and then out the reed valves into the exhaust for more complete combustion.
That's the way I think it works, again I could be wrong.
I think you are right. Both explanations (mine & yours) has the same goal : burning of unburned gasses (afterburner process). Regarding my theory, maybe you cannot introduce unburned gasses back to airbox, also due to high temp of those ...... just IMO.
AngelWolf says "Due to EPA regulations, Kawasaki has some interesting equipment on our engines. It's purported to recycle some of the unburnt exhaust gases through the engine, burning them off and thus reducing emissions. What the system manages to do is make the exhaust pipes hotter than Hell, and in most cases (especially when coupled with the lean factory mixture setting) causing popping in the pipes during decelleration and occasional backfires."
Your idea also explain why the pipes are so hot, as Wolf said, this is due to the fresh air (oxigen) which cause unburned gasses to burn into the pipes ... IMO.
In the picture (I take it when I adjust valve clearance) we can see that fresh air is not going to the top cylinder head, but through the reed valves to exhaust port. Exactly what you said.

This is why i love forums ....we all can learn .... :)
 

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