PAIR valve removal

[RZ]

Hi everyone...
i tried remove PAIR valve(cbr600 f4i)
(remove PAIR, connect 2 breather hose and 1 suction hose)

i read a rules, but i'm not sure..

PAIR valve remove and blockoff(or connect all)
is illegal?

[RZ]

Hi everyone...
i tried remove PAIR valve(cbr600 f4i)
(remove PAIR, connect 2 breather hose and 1 suction hose)

i read a rules, but i'm not sure..

PAIR valve remove and blockoff(or connect all)
is illegal?

[Ockham]

Competition rules don't require running PCV, but don't block off the vent barbs. It's okay to plumb them together, and then to your PCV catch can with no valve in the setup, assuming that's what you're talking about. Just, whatever you do, don't block the PCV system entirely.

[blur95]

Can you explain why? It seems to be a popular mod in the sportbike community, and I have found a racing parts company that makes pair block-off plates for the f4i.

[RZ]

i read this article

"it makes the bike better all around and alot of people agree ,i have even seen dyno test that show increased torque and horse power"

http://cbrforum.com/forum/showthread.php?t=56964

[RZ]

i read this article

"it makes the bike better all around and alot of people agree ,i have even seen dyno test that show increased torque and horse power"

cbrforum.com/forum/showthread.php?t=56964

[Tech Guy]

The reason ANY engine needs to vent the crankcase and/or the cylinder head cover is to allow any blow-by gases to escape. And it does not matter whether it is an F1 engine or your road car engine, the same thing applies. Piston rings cannot make a perfect seal and all engines have some blow-by!

If you plug off all the vents, you will build up pressure in the crankcase and it is likely you will blow out a seal somewhere, and deposit oil where no one wants it, let alone the FSAE organizers. It appears from the modification that RZ references, that hose #3 is thrown away - isn't that the one that comes up from the vent on the gearbox/crankcase? Ands that this modification leaves that vent open. The FSAE tech people will want a hose on that nipple and the hose to go to the catch bottle.

[Wesley]

We block off both vents on the valve cover with aluminum plate. (They aren't crankcase vents, they recirculate from the exhaust ports.)

There's a separate PCV vent that exits on the valve cover on the left side of the engine. That's the one you should route to your overflow can.

[Tech Guy]

Wesley,
So what you are blocking off or removing is the EGR (exhaust gas recirculation) system. Completely acceptable and a good idea.

[Ockham]

@Wesley: Are you sure that the outside vents on CBR valve covers are some kind of EGR system? We had this debate early in the year on my team, and I couldn't see how they connect to the exhaust system. I'm used to EGR provisions connecting directly to the intake manifold, but I guess gases could feed through the same hose as the PCV system. Seems odd to send exhaust gas through a rubber hose...

[Brian Barnhill]

It's not an EGR in the sense of that on some cars, but it is an emissions control device.

"The exhaust emission control system consists of a secondary air supply system which introduces filtered air into the exhaust gases in the exhaust port. Fresh air is drawn into the exhaust port whenever there is a negative pressure pulse in the exhaust system. This charge of fresh air promotes burning of the unburned exhaust gases and changes a considerable amount of hydrocarbons and carbon monoxide into relatively harmless carbon dioxide and water vapor. The PAIR system is controlled by the ECM using check valves and a solenoid."

I've always removed the PAIR system and added block off plates and hooked up the hose on the left side of the crank case (normally to the PCV/Airbox) through our catch can. Always passed tech, no problems running the engine.