Hayden Krank Vent Plus

[OldVet66]

I recently got a Hayden krank Vent Plus to test the effects of a constant vacuum on the crank case. These valves are ported so the one way umbrella valve will only maintain 3 to 5 lbs. of vacuum at all RPM's in the crank case. I have got to say they work very well. Instantly I noticed the idle smoothed out a lot, and there is a lot more low and mid range power. That linked with the vacuum sync ports crossed over between 1/4 and 2/3, I believe I have gotten back everything lost on the low and mid range with the stage three jet kit and K&N pods and Vance and Hines 4 into one exhaust. That's the good news. The bad news is that the valve failed in about three days, sticking in the closed position. Hayden says that fuel in the oil is the only thing that can make the umbrella valve fail like that. While the valve was being sent back to the factory for testing and valve replacement, I immediately changed oil, checked the petcock, and did a check with a clear fuel level test gauge on each bowl watching the fuel rise to it's cut off level and a running idle test, bike on center stand and leveled. All four bowls are dead on spec. on the lower side of the bowl rim, spec. being from the bottom to the top of the rim. I captured and sealed some of the oil I changed, and it didn't have any more fuel smell to it than you would expect from oil that needs to be changed. I got four different mechanics to smell it because my sinuses are really messed up this spring. I believe the valve was a defect, but if fuel is contaminating the valve, how is it getting there? The compression is good on all four cylinders. Could it be that fuel vapor is being sucked directly passed the old valve seals into the valve cover? It may not be a concern if the valve was defective, but this Hayden valve works so well that I don't want to give it up. I got it back today and installed it where I can reach it easily for service and extended the tube down below the muffler with the float bowl overflow vents. Again the idle changed from a mild lope to sewing machine smooth, and bottom end power is way up. One thing I can say for sure, these motors love a vacuum in the crank case and if it will be reliable, it is a definite upgrade for a much improved low end. I rolled it on smoothly from 2000 RPM in fifth gear, without any of the traditional VM coughing. I didn't snap open the throttle, but I also didn't wait for the carbs to catch up either. That has never happened before.

[AJ]

Interesting to hear you installed this valve, OV66. The Harley guys love them, but it sounds like it works well on your old Suzook.

Keep us posted on how the new valve holds up, and any other results like fuel and oil consumption.

[rich001]

Ditto to AJ. I too am interested in ant consequences (good or bad) of using one of these.

Can anyone explain how they work? I understand it is a valve within a body opening and closing. Does it open and close with the pulsing within the crankcase? How does this actually create vacuum? I can see how it would stop pressure, but vacuum?????

Richard

[G. Bruns]

Uh...call me dense, but how exactly is this inline filter installed? Any guess as to why it is seemingly only marketed to Harleys?

[AJ]

A word of explanation for GB and Rich above.

First, the valve is connected to the crankcase breather port, usually on top of the valve cover. This is very similar to the PCV (positive crankcase ventilation) valve in your automobile engine.

Think of a bicycle pump. There is a piston that pressurizes air into a hose and into a tire (the high pressure reservoir or "tank"). Push on the pump handle and you pressurize the air in the pump and force it into the hose. A check valve seals the hose to hold in the pressure. Now pull up the handle and suck more outside air into the piston, compress it again and force more air into the hose again, raising the pressure.

Now turn it around with the check valve on the other side (the low pressure side). Have the piston draw air out of a tank (the low pressure tank). The check valve closes, the piston pushes the air out of the system and begins to suck more air out of the tank, the check valve closes again and the pressure is reduced inside the tank.

This latter case is essentially how the Hayden valve works as a check valve. The piston action in the crankcase pumps a little air out from underneath the pistons. The Hayden check valve closes and doesn't let air flow the other way.

In a Harley, the pistons are connected to a single crank pin. It's a little hard to visuallize, but the pistons sort of rise and fall together, changing the volume underneath them, changing the volume of the crankcase. Because of this, the Harleys first suck air into the crankcase as the pistons rise on the compression (and exhaust) stroke, then the push air out of the crankcase as the pistons move down on the power (and intake) stroke. If you feel the crankcase breather on a Harley, the engine is always either puffing out air or sucking in air. It's quite dramatic compared to a four cylinder inline engine. The Hayden check valve only lets air out of the crankcase, so that a slight vacuum forms in the crankcase.

The effect should not be so great with an inline Suzuki four cylinder, but OldVet66 is experimenting with it and seeing interesting results. I hope this explanation helps.

[G. Bruns]

Thanks for the explanation!

[rich001]

Thanks AJ, a most enlightening explanation. I can see, as you explain, how Harleys would benefit. BUT with Suzuki 4s ???????????

Still, the old vet has felt the difference and I, for one, would love to find a simple improvement like this vent. So I look forward to updates with baited breath.

Richard

[AJ]

Might be of interest... http://www.nightrider.com/biketech/crankvent_test.htm

[OldVet66]

There is definitely a difference with the Hayden valve. Keep in mind that it is designed for early model Harley evolution motors to keep them from blowing gaskets. I got mine shortly after a friend of mine got one for his early EVO. His base gasket was leaking oil, with the Hayden valve it doesn't leak much at all. I installed mine and noticed an immediate difference in low and mid range power and a smoother idle. His valve and mine both failed closed within two days. Hayden immediately replaced both umbrella valves. There were different markings on the rubber of the first valve. Both valves have been running for a while now without a problem, so the initial valves seemed to be a defect or the wrong valve. I ran the valve down by the clutch this time, instead of right off of the vent on the valve cover, and extended a hose below the muffler with the float bowl vents. It seems to be a better location, it doesn't get any crank case moisture and oil build up in this location and I can service it if necessary without having to lift the tank. Since the replacement valve, my average gas mileage has gone up from 38/39 to 41/42mpg. I can't say there is any horse power gain, but there is much better drive-ability as a result of the valve (more low end and low mid range power). the way I have it set up, the next time I get together with AJ, we can put it on his 1100 and see if he notices any benefit. The valve is a one way valve that is ported so that it can only achieve a 3 to 5 lb. crank case vacuum. It was also explained to me that at high rpm especially with the four cylinder bikes that the venting going in and out of the crank case breather becomes so fast that it effectively creates an air dam allowing a positive crank case pressure to build up behind it. The Hayden valve eliminates this and maintains a constant 3 to 5lb vacuum at all rpm's. https://picasaweb.google.com/rsmith6...eat=directlink