Pair Plates Q - Wrist Twisters
 
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post #1 of 28 Old 07-26-2010, 10:51 AM Thread Starter
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Pair Plates Q

so a few months ago i removed the pair plates and isntalled the nice block offs made by semigray. its hard to explain, but my bike just doesnt feel the same. i understand the factory part is made to vent the valve cover and these are sealed up. has anyone felt any negatives differences from installing these and could their be bad long term affects from having the vent blocked off? it seems maybe another option would be small filters to vent on the pair plates. any input would be appreciated

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post #2 of 28 Old 07-26-2010, 11:00 AM
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I ended up going with a small crank case breather style filter on mine, seems to be working well. I think that as long as it is not vented back into the air box you will have all of the same positive effects as blocking them off.

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post #3 of 28 Old 07-26-2010, 11:52 AM Thread Starter
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so you just put a small breather on the factory pair piece?

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post #4 of 28 Old 07-26-2010, 02:21 PM
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either a) your perception is wrong or b) you did something wrong during the work.
maybe you left a vac line detached, maybe a plug boot isn't ALL the way snapped down. the PAIR valves are NOT the PCV system, so the two have nothing to do with each other.

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post #5 of 28 Old 07-26-2010, 05:37 PM
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Quote:
Originally Posted by bucky View Post
either a) your perception is wrong or b) you did something wrong during the work.
maybe you left a vac line detached, maybe a plug boot isn't ALL the way snapped down. the PAIR valves are NOT the PCV system, so the two have nothing to do with each other.
The Pair system allows air to be entrained into the exhaust only on decelleration, correct? I also think something else is amiss...not the Pair system.

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post #6 of 28 Old 07-26-2010, 05:53 PM
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like everyone else has said... the pair system has nothing to do with crank case / valve cover venting.... that one is on the back throttle side of the motor.

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post #7 of 28 Old 07-26-2010, 07:02 PM Thread Starter
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hmmm k. i just thought it was a form of a pcv cause the hose runs back into the air box. maybe its just my perception. ill double check the work but maybe its just in my head

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post #8 of 28 Old 07-26-2010, 07:30 PM
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Quote:
Originally Posted by hornet919 View Post
hmmm k. i just thought it was a form of a pcv cause the hose runs back into the air box. maybe its just my perception. ill double check the work but maybe its just in my head
it does run from the air box, you are correct.

Quote:
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.
Removal of the PAIR system will yield three main benefits: 1) weight reduction 2) reduction of engine compartment clutter 3) increase in the scavenging ability of the exhaust system

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post #9 of 28 Old 07-26-2010, 08:40 PM
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Nice explanation, but, what engine is that?

Not a 919! Of course, the description is the same, as is the function.

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post #10 of 28 Old 07-26-2010, 10:46 PM
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Quote:
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Nice explanation, but, what engine is that?

Not a 919! Of course, the description is the same, as is the function.
RC51 by the looks of it!

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post #11 of 28 Old 07-27-2010, 02:45 AM
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RC51 by the looks of it!
man knows his engines

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post #12 of 28 Old 07-27-2010, 06:36 AM
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Quote:
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RC51 by the looks of it!

DINGDINGDING! Way to go!

By the way, does anyone else see the angry face profile under the left-side piston? The nose is almost touching the word "port". Rorschach it is not, but, it just caught my eye...

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post #13 of 28 Old 07-27-2010, 07:06 AM
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Quote:
Originally Posted by Blackheart View Post

By the way, does anyone else see the angry face profile under the left-side piston? The nose is almost touching the word "port". Rorschach it is not, but, it just caught my eye...
I think you need a vacation, Blackheart!

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post #14 of 28 Old 07-27-2010, 08:20 AM Thread Starter
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Quote:
Originally Posted by Blackheart View Post
DINGDINGDING! Way to go!

By the way, does anyone else see the angry face profile under the left-side piston? The nose is almost touching the word "port". Rorschach it is not, but, it just caught my eye...
now that you mention it, i see it as well.

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post #15 of 28 Old 07-27-2010, 08:33 AM
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Quote:
Originally Posted by hornet919 View Post
so you just put a small breather on the factory pair piece?
Yeah. It seemed like a good way to go.

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post #16 of 28 Old 07-27-2010, 09:25 AM
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Quote:
Originally Posted by bwoso View Post
I ended up going with a small crank case breather style filter on mine, seems to be working well. I think that as long as it is not vented back into the air box you will have all of the same positive effects as blocking them off.
completely negates the whole point of doing a pair blockoff... its to make it to where NO air is passed through the pair ports so you dont get deceleration popping.... the small amount of air that gets pulled from the air box (no air gets pushed into the airbox) does not effect or make any performance hit. To have the ports vented ALL the time probably screws with stuff quite a bit... as there is an ECU controlled cycloid that controls when air can be pulled from the airbox on the stock setup... another positive side effect of pair plates is the fact it cleans up underneath the tank.

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post #17 of 28 Old 07-27-2010, 10:22 AM
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to offset your angry rc51 face, i have surprised combustion chambers.
Attached Images
File Type: jpg combustion face 5 7.jpg (56.6 KB, 9 views)

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post #18 of 28 Old 07-27-2010, 10:51 AM
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^ LOL

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post #19 of 28 Old 07-27-2010, 10:54 AM
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"got a machine head, it's better than the rest, green to red, machine head"

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post #20 of 28 Old 07-27-2010, 11:01 AM
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Quote:
Originally Posted by bucky View Post
to offset your angry rc51 face, i have surprised combustion chambers.
Looks like a Lemur from the Madagascar Penguin Movies.

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post #21 of 28 Old 07-27-2010, 04:01 PM
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Quote:
Originally Posted by nd4spdbh View Post
completely negates the whole point of doing a pair blockoff... its to make it to where NO air is passed through the pair ports so you dont get deceleration popping.... the small amount of air that gets pulled from the air box (no air gets pushed into the airbox) does not effect or make any performance hit. To have the ports vented ALL the time probably screws with stuff quite a bit... as there is an ECU controlled cycloid that controls when air can be pulled from the airbox on the stock setup... another positive side effect of pair plates is the fact it cleans up underneath the tank.
Isn't the reason for the popping the fact that the dirty air goes back into the motor. And how would unplugging the hose from t
he air box and putting a filter on it change how much air vents out anyway?

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post #22 of 28 Old 07-27-2010, 04:26 PM
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Originally Posted by bwoso View Post
Isn't the reason for the popping the fact that the dirty air goes back into the motor. And how would unplugging the hose from t
he air box and putting a filter on it change how much air vents out anyway?
There are at least three things needed for something to "burn". Oxygen, fuel, high temperature...the higher the better.

On deceleration, filtered air is being allowed to go from the airbox, through the vacuum-operated valve, and into the exhaust. This filtered air contains about 20.9% oxygen (compared to almost no oxygen in the exhaust that just exited the cylinder into the pipe), and the incompletely burned fuel that just exited the cylinder is THEN burned in the pipe (Oxygen, fuel, temperature)....POP.

Some people call it "lean pop", which isn't telling the entire story. Lean burning exhaust is hotter than rich burning exhaust...so, the exhaust pipe is hotter. It is hot enough to stimulate whatever unburned fuel there may be, to then ignite in the pipe....POP. This time, it's because the temperature is so high (remember, the higher the temp, the more likely to ignite) rather than due to the introduction of oxygen (as in the PAIR system).

At least, that's how I think about it. Maybe it's not entirely correct...I'd be interested in a more correct explanation if someone has one.

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post #23 of 28 Old 07-27-2010, 04:30 PM
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Quote:
Originally Posted by bwoso View Post
I ended up going with a small crank case breather style filter on mine, seems to be working well. I think that as long as it is not vented back into the air box you will have all of the same positive effects as blocking them off.
You better hope that the crankcase breather you are using is filtering the air well, as the intake box is certainly sucking air through that filter into the air box....unless you have a one-way valve on it...in which case, it is doing nothing.

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post #24 of 28 Old 07-27-2010, 04:36 PM
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black heart got it.... under the pair plates / pair housing on the left and right of the motor are Reed valves that only allow air to move one way... from the airbox out the exhaust.

Go to auto zone and get some big vacuum caps to cap off the PAIR system at the top of the motor AND at the airbox.

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post #25 of 28 Old 07-27-2010, 04:40 PM
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Quote:
Originally Posted by hornet919 View Post
so a few months ago i removed the pair plates and isntalled the nice block offs made by semigray. its hard to explain, but my bike just doesnt feel the same. i understand the factory part is made to vent the valve cover and these are sealed up. has anyone felt any negatives differences from installing these and could their be bad long term affects from having the vent blocked off? it seems maybe another option would be small filters to vent on the pair plates. any input would be appreciated
did you seal those plates?

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post #26 of 28 Old 07-27-2010, 05:28 PM
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Quote:
Originally Posted by zaq123 View Post
did you seal those plates?
He shouldn't have needed to.

The plates I made have blind holes in the backside allowing the reed valves to remain in place.

The top half of the reed valve assembly seals on the lower surface of the plates, just like they did with the original covers.

Now if the reed valves are removed.................

I plan to die young, as late as possible.
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post #27 of 28 Old 07-27-2010, 08:03 PM
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Not helping much here, I just wanted to say how nice semi_gray's plates are, especially with the blind holes machined into the back for easy installation, and a polished mirror finish. Excellent.

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post #28 of 28 Old 07-28-2010, 05:08 AM Thread Starter
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Quote:
Originally Posted by semi_gray View Post
He shouldn't have needed to.

The plates I made have blind holes in the backside allowing the reed valves to remain in place.

The top half of the reed valve assembly seals on the lower surface of the plates, just like they did with the original covers.

Now if the reed valves are removed.................
i simply removed the stock pieces and installed the plates. they are super nice which is why i was hoping it wasnt them making any problems. after reading everything here and learning a little more about the pair system, i have come to the conclusion that there is no way they could be causing the problem. it could be my PCIII map i suppose

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