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Discussion Starter · #1 ·
i know the pair-mod subject has been posted several times, but i want to post my experience. i'm finding the best detail info was on bugmans website. what i did was vent the crank and T'd it to the pair valve ports, and plugged the two airbox holes. it was also posted you can remove the pair valve selenoid and put a 20ohm resistor in its place. everything worked except i fried the my resistor. i ended up using the wrong voltage resistor (22ohm, 0.5watts radio shack).

so what i did was i left the hoses in place and put the pair valve selenoid back (back in the electrical system) w/ no hoses hooked up. this worked fine. here is where i should have stopped....!!!!

of course on my quest to find more power, i read this busa site they plug the holes and install block off plates, blah, blah, blah... i got to thinking, why not plug the crankcase and pair valve ports. (mind you, i'm a gas tank taking off fool) so i plug the ports and put everything back. once again, thanks to bugmans site, he provided info to test the negative back pressure. i turned the bike on and let it warm up. i turned it off and went to remove the oil filler cap and as i was turning it i could hear the pressure really sucking in some air. it was sucking in so much air once it got to a certain point it shot the cap at my face. funny right. i was thinking dag, i really got negative back pressure now. i tested it a couple more times and thought, this is really sucking in some air. anyways, i went for my ride and after about 30 miles i had oil all over the right side of my bike. i got the bike home and did some investigation....

i got the bike apart and all the plugs were still in place. it looks like the negative back pressure was too high and it shot oil out of my filler cap and right side crank cover (not sure what this is called but its the cover where you fill the oil and adjust the clutch). i put the hoses back in to vent the crank, t'd at the pair ports. i even tried to tighten the screws on the cover again but it still leaks slowly. enough to scare you wondering if oil is getting on your tire.

i know this is alot of jibber jabber, but i highly recommend venting the crank, t'd to the pair ports. and leaving your pair valve selenoid in the electrical system.

any recommendations on what i can use to make another gasket? i know track auto/napa has those gasket kits. any help would be appreciated....



be safe out there, David....
 

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This is just speculation, but are you sure you hooked everything up right? Negative pressure when you released with the cap would have SUCKED the cap in, not blown it out at your face... Also if you were running negative pressure, even if your gasket was leaking, etc.. It would have caused it to suck air IN through the gasket, not blown oil out... Sounds to me like you were running POSITIVE pressure in the crankcase, not negative...
 

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I don't know where you got this info and how you could possibly misunderstand but no one recommends plugging the crankcase vent!!

Not understanding the difference between negative and positive pressure = not too bright.
Blocking off the crank case and then going for a ride = very not too bright.
Not crashing because oil from the blocked off crank case got on the rear wheel = lucky.

Be smart out there...
 

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CC must be vented, either to the airbox or out the PAIR valve.......it's quite simple. Vented through the PAIR valve out to the exhaust, you will get no negative pressure.
 

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In the quest for HP sometimes you win and sometimes you loose.

I am not going to make any negative comments as the key is at least you tried something and were able to learn from it.

Also on the bright side you were able to warn others.
 

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I've had a Busa for 5 years prior to the K5 and had the PAIR mod installed.

FYI... Here's what it's supposed to do.
Eliminate pumping loss's by pulling negative pressure in the crankcase.

Here's how it works...
The PAIR valve has ports that intersect the exhaust outlets at about a 90 degree angle. When the exhaust pulse passes over the port the pressure in the port is lowered creating a venturi effect vacuum. The four ports are plummed together via a junction box (with a reed check valve in it) and then connected to the airbox. The principal is to draw clean air into the exhaust system to permit burning off of any unburned hydrocarbons. Disconnect the hose from the airbox and you have a vacuum pump. Connect it to the crankcase vent and you're pulling a vacuum in the crankcase.

Here's how it needs to be hooked up (should you want to do so)
Disconnect the PAIR hose from the airbox and plug the nipple on the airbox.
Disconnect the crank case vent hose completely and plug the nipple on the airbox.
Connect the PAIR hose to the crank case nipple on the motor.

Here's what I think happened to you based on my experience with the busa.
1. You hooked it up incorrectly. If you plugged the the cank case vent on the motor... the action of the pistons down stroke created positive pressure and the oil was pushed out through the seals.

2. You hooked it up correctly but the stock hose collapsed as a result of the vacuum imparted to it.
The PAIR system when hooked up to the airbox in the stock configuration see's no vacuum since the airbox is always open. As a result...Suzuki uses a tube with very little side wall stability. If you use the stock hose... it will collapse under vacuum when connected to the crank case vent. Once the hose collapses the vacuum holds it shut. Enough so that a plug is created and the pressure rises in the crank case. Once again...positive pressure, etc. etc.

If you do decide to try it one last time... make sure that you use 3/8 or 1/2 braided vinyl (PVC) hose that is vacuum rated. You can get it at Home Depot. Also use hose clamps to ensure a good seal.

I did hook up a vacuum guage to my Busa and the mod pulled 8in/Mercury or about 2psi of negative pressure. There were some dyno tests done although not by me and the going consensus was that the mod made about 2 hp.
 

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fwiw, i have the 22ohm resister on my k5 racebike and have had zero problems
 

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Discussion Starter · #8 ·
hey R.U., i know it sounds weird but what i was trying say is while i was turning the cap, it was sucking in the air fast and i guess it had so much pressure it got air and once i got to the last threads it shot the cap out. trust me, i tested it a couple of times and the negative pressure was real high.

stam, i actually got some good info from you, but i was trying to be creative and made a mistake.

webcrush, if you have the right watt 22 ohm resistor you are good. i think i didn't and thats why mine fried. the only reason why i didn't take a pic of it was my digital camera can't focus that small.

i still have a little leak coming from that right case. any recommedations on what i can use to make another gasket? also, whats the torque specs for tightening those case screws?

hey RRaider, you are right, you win some and you lose. but isn't great when you find a mod that keeps you out front and they wonder what you got done, heheheee....LOL.
 

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Discussion Starter · #9 ·
one more thing, i do know the difference between negative and positive pressure. how i checked mine was by unplugging the oil filler cap, turning the bike on, plug the hole with my thumb, then turn the bike off. you can fill it sucking your thumb when you remove it.

once again, i'm an egg head and tried to look for more ponys. it's back vented just need to fix this tiny leak.
 

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Okay, so you know it's not negative pressure that is shooting out the oil fill cap then.
I checked the effect of the pair mod with a vacuum gauge and I got 2in at idle and 8in down the back straight.

Never, NEVER block off the crank case vent.
 

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Okay, so you know it's not negative pressure that is shooting out the oil fill cap then.
I checked the effect of the pair mod with a vacuum gauge and I got 2in at idle and 8in down the back straight.

Never, NEVER block off the crank case vent.
Looks like you got the same numbers that I did with my old Busa. I agree... negative pressure will never blow out any oil.
My guess is that if he used the stock hoses his hose either collapsed or got kinked after the tank was bolted down.
 

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Discussion Starter · #12 ·
Stam, thanks for the info. before i do anymore mods i'll get with your R&D guys, heheheeee....

FLGixxer, i got some friends from florida telling me about dudes down there running 9/10 of mile @195mph. thats moving. i need to get my bike running like that. are you one of those dudes? the secret is that yosh 4-1 japan w/ oil offset pan. of course there is probably other mods but man thats breathing......195mph....!!!!
 
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