Yamaha R6 Forum: YZF-R6 Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
9 Posts
Discussion Starter #1
OK I am new to the forum and amung the helpful things i am reading a few things i find absolutly backwards. I have been on Dirt bikes ATV, shifter karts blah blah blah....for a long time.
07 R6
Graves block off: everyone is saying the graves block off removes the air pump on top of the engine, i agree. The air pump is explained to pump air into the exhaust to burn unburnt fuel, i disagree. It only pumps the crankcase air into the air box to be mixed with the clean incomming air. there is no spot on the exhaust that anything can be pumped into. i have checked the service manual and had my bike apart a few times this pump is not pumping into the exhaust but into the air box to relieve the blow by from the crank case. I have been a car mechanic and a state inspector and the purpose of this is to take the blow by gasses ( gasses that slip past the piston rings) which are basically exhaust gases and put them into the intack track so they get processed by the cat. i don't think i have a problem with disconnecting this hose to the air box as it lets oil and nasty stuff in there as well as diluting the oxygen content of incomming air. But if you block these ports off where is your crankcase venting too??? is there another vent i don't know about??? an engine will run with these ports blocked off, but it is not good to let pressure build in there. I plan on putting a small filter on the end of the hose that goes into the airbox so it vents to the atm, or I may just remove the pump and put small filters on the stock nipples and cap off the hole in the airbox. Everything i know about engines tells me that this mod will just give you oil saturated in unburnt fuel and a f!cked up engine. Can someone please correct me if i am wrong???
 

·
Now you see me...
Joined
·
1,275 Posts
i don't have a clue about it. :dunce: you make a good point though.
 

·
Just Burnin Time
Joined
·
2,220 Posts
a VERY good point, to the point i want to put mine back on maybe....


Subscribed for knowledgeable input.
 

·
Premium Member
Joined
·
11,269 Posts
i dunno it seems like a good point. this is from tobefast.com:

Description: Graves Motorsports Smog Block Off Plates are designed to seal off the ports on the valve cover used by the air injection system (a.k.a smog pumps or AIS).

The air induction system (AIS) burns unburned exhaust gases by injecting fresh air (secondary air) into the exhaust port, reducing the emission of hydrocarbons.

Once these are capped off the air injection system can be safely removed. These Smog Block Off Plates are made from CNC'ed billet aluminum and feature the Graves Motorsports G logo. There are two reasons why you want to remove the air injection system from your bike;

* 1. If you are using your motorcycle on a closed course (racing, track days, etc.) you will want to remove all unnecessary equipment from your bike for reduced weight and ease of maintenance.
* 2. To get an accurate Air:Fuel (A/F) ratio when dynoing the bike. The air injection system pumps fresh air directly into the exhaust stream in order to burn off any unused fuel. Unfortunately by doing this the A/F ratio is thrown off by the extra fresh air in the exhaust stream. By removing the air injection system you can achieve an accurate A/F ratio.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #5
I called a friend of mine who works at a dealer and races bikes. he said I am 100% right, the people who can get away with block off's are the guys that race and tear their engines down every week. as far as the graves site it is 100% incorrect the pump does not inject gasses into the exhaust look at your bike or a SM it is clear as day. The addition of crankcase gasses into the air box only dilutes the oxygen content of incomming air it does not affect the A/F ratio reading. I was told it is better to leave it alone you won't get any oil in there on the new bikes unless there is too much oil in the crankcase. if you really feel you need to modify it don't cap it off put a filter of some kind on it.
 

·
Registered
Joined
·
115 Posts
first of all i am no certified mechanic and in no way calling anyone a liar but more or less just putting up another idea. with that said maybe the pump allows air to be injected into the exhaust chamber to mix the exhaust with fresh air in the head before it hits the header saving another hole to be put into the exhaust. again this is just another idea and in no way am i trying to offend anyone. just more ideas.
 

·
Registered
Joined
·
96 Posts
I called a friend of mine who works at a dealer and races bikes. he said I am 100% right, the people who can get away with block off's are the guys that race and tear their engines down every week. as far as the graves site it is 100% incorrect the pump does not inject gasses into the exhaust look at your bike or a SM it is clear as day. The addition of crankcase gasses into the air box only dilutes the oxygen content of incomming air it does not affect the A/F ratio reading. I was told it is better to leave it alone you won't get any oil in there on the new bikes unless there is too much oil in the crankcase. if you really feel you need to modify it don't cap it off put a filter of some kind on it.
we have the graves b.o.p. on our race bike (fully built) which we DO NOT tear down every weekend (or at all for that matter) and have yet to have any problems. what kind of racing does your friend do?
 

·
I like ice cream!
Joined
·
1,350 Posts
first of all i am no certified mechanic and in no way calling anyone a liar but more or less just putting up another idea. with that said maybe the pump allows air to be injected into the exhaust chamber to mix the exhaust with fresh air in the head before it hits the header saving another hole to be put into the exhaust. again this is just another idea and in no way am i trying to offend anyone. just more ideas.
That's my exact interpertation of the functionality of the block off plates. They block the ports where clean air would be pumped into the exhaust to clear emisions or epa or whatever.
 

·
Registered
Joined
·
2,472 Posts
there is another crank case breather hose. It comes off from on top of the tranny section behind the starter and connects to the "rear" part of the airbox. That is what the stunters mod to reduce oil in the airbox during long wheelies and stoppies. As far as the description, yes its a little misleading, but if you're looking to buy these, you basically know what they're for, to get rid of the air pump, and thats exactly what they do.
 

·
Avid Enthusiast
Joined
·
7,408 Posts
Now the only reason i feel that i can say anything here is because i just so happen to be cutting the cat off of my bike and i could look into this a bit. So what ive found is that there is another line for crankcase pressure to dump into the air box (pic to follow shortly). It comes from the top of the transmission and into the back of the airbox right above the fuel rail. Since the oil goes from trans to clutch to engine, not exactly in that order, but still any pressure built up is vented at the transmission not out of the valve cover. As my buddy puts it "a common crankcase". I'd like tell you im no ASE certified tech but the truth is i am but as an added bonus I did stay at a holiday inn express last night.
 

·
Registered
Joined
·
9 Posts
Discussion Starter #11
OK i read these posts and decided to look in the service manual. page 7-15 i was incorrect and so was the person i was talking to. Sorry i had to be the guy passing bad second hand info. The air pump, not actually a pump but a valve, actually allows air from the airbox through the casting in the head and into the exhaust ports. So the crank case must vent through the hose in the back of the engine cases. If the service manual is correct, i think we can assume it is, then there should be no problem with the block offs and what is written on the web site for graves is correct. I am assuming that anyone who has had their head ported has these ports blocked off and smothed over??
 

·
Registered
Joined
·
313 Posts
I just installed mine two nights ago and they are placed right over the exhaust valves and allow air from the box to mix with exhaust leaving the engine. You're findings in the service manual are correct. They work just fine.
 

·
FAST 07 RED R6
Joined
·
200 Posts
I almost got a little scared when reading this post because i was only days away from putting mine on!!
 

·
Registered
Joined
·
42 Posts
i got graves block offs on my 06 with 28,000 miles with no problems
 

·
iCrash
Joined
·
1,912 Posts
the PAIR isnt a crankcase breather on these bikes, you wont have any issues w/ blocking these off and reliability.

the PAIR injects air into the exhaust side of the valve train under decel, which causes a popping sound on bikes w/ a aftermarket exhaust due to excess fuel getting burned off, this also throws off the A/F mixture when tuning the bike and it must be disabled to get an accurate reading.

whoever said this is a mod only for bikes that get torn down every week isnt correct.
 

·
Registered
Joined
·
46 Posts
I bet if you look in the exhaust ports with a flash light you will see a hole in the side. That is were it should vent to. I could be wrong on this motor, I had a 1991 Toyota MR2 turbo and it's cyl head was designed by Yamaha and it vented out the #4 exhaust port.
 

·
Zombies may bite!!!!
Joined
·
1,182 Posts
I think there was just confution on what way the air flowed, and not thats cleared up.

:)
 
1 - 18 of 18 Posts
Top