Engine venting

[ZEERX]

I've read every message about removing the emissions stuff I could find and for me the jury is still out. But the question I did have is shouldn't the engine (cases/top end) be vented? Every engine I've ever seen be it car or bike has some kind of vent to the air. Wouldn't a build up of pressure start to push oil through the seals and gasgets? Maybe there's another vent on the engine that I missed. Whatdoyathink. Rich.:confused:

[Rick61a]

Engine breather is on top of the tranny, theres a tube that goes to the airbox. The stuff on the valve cover isn't an engine breather

[vancer]

Originally posted by Rick61
Engine breather is on top of the tranny, theres a tube that goes to the airbox. The stuff on the valve cover isn't an engine breather Rick61, What does the stuff on the valve cover do then? :confused: (also) Can block off plates be fabricated from flat alloy stock instead of buying the Muzzy ones?

[YTRAP]

Block off plates can be fabed or can be plugged from under the valve cover. I tapped and plugged mine. Lost the valve cover locating dowels which are actually the tubes into the exhaust. I never had trouble locating th evalve cover anyway.

[rockon1]

Sucks air out of airbox ,directs it into the exhaust through reed valves in cover. Bogus emissions crap..... Various ways to block reeds without buying plates(though I like/bought them). You can connect two hoses together with small pipe and clamps or thead existing plates and use (pipe plugs I think).....

[red]

Rockon.... I know you responded to this back in Oct 02, but I've been doing a bit of reading on emissions removal throughout this thread and I have a question. I just want to make sure I don't screw up a great runnning stock Rex as I prepare for mods. If the emissions crap suck air from the airbox and direct it into the exhaust through the reed valves in the cover, as you explained, what then occurs in that reed valve area when you block it off? Does it just cease to attempt sucking once it's blocked off, because I would think that some vacuum from somewhere causes the air to be sucked. I would think that the lack of that air being pulled would cause the engine to suffer or faulter in some way since it was designed to do such. I'm not trying to make a mountain out of a mole hill, I just want to understand the inner workings of the engine a bit better. Thanx
red

[rockon1]

Originally posted by red
Rockon.... I know you responded to this back in Oct 02, but I've been doing a bit of reading on emissions removal throughout this thread and I have a question. I just want to make sure I don't screw up a great runnning stock Rex as I prepare for mods. If the emissions crap suck air from the airbox and direct it into the exhaust through the reed valves in the cover, as you explained, what then occurs in that reed valve area when you block it off? Does it just cease to attempt sucking once it's blocked off, because I would think that some vacuum from somewhere causes the air to be sucked. I would think that the lack of that air being pulled would cause the engine to suffer or faulter in some way since it was designed to do such. I'm not trying to make a mountain out of a mole hill, I just want to understand the inner workings of the engine a bit better. Thanx
red



Dont sweat it. Its the flow of exhaust gases that "draws" air through the reed valves. Once its blocked off its just dead ended.The exhaust gas doesnt know or care! It really has no affect on performance either way....

[red]

Thanx, bro..:thumbs:

[rockon1]

Originally posted by tanner
My bike , since the bigbore kit , makes lots of popping and crackling exhaust noise under decelleration-- sounds kinda' cool but , in time I think it'll just get irritating. Is this bad ? Is it caused by not blocking off the " emission crap" ?



They should help.Ive never had my emissions cap on long enough to really tell ya first hand!:laff:Popping wont hurt anything but if it annoys you make some "block off" plates and maybe turn your mixture screws out a bit-depending on where they are set now.

[Rubba]

Originally posted by tanner
My bike , since the bigbore kit , makes lots of popping and crackling exhaust noise under decelleration-- sounds kinda' cool but , in time I think it'll just get irritating. Is this bad ? Is it caused by not blocking off the " emission crap" ?

Sounds lean on the idle jets. Done any carb work with that big bore? Done any airbox or exhaust mods?

[rockon1]

Originally posted by tanner
did full muzzy, removed airbox , and running 140's and 145's on the jets. It really runs great except for the popping. Muzzy was very specific with jet size, pipe, air filter, cam timimg . They sent exactly what I ( my dealer mechanic) was to install . I'm gonna' take it to factory pro's dyno and let them fiddle with it in a couple weeks though...maybe if they say everything ismixed right then I'll try blocking off the plates. I want to check around thoroughly first though you know?


Nothing to lose with trying block off plates- especially if you make a set...;) Also turning out the mixture screws a tad is relatively harmless too...

[StrongPerf]

Originally posted by red
Thanx, bro..:thumbs:

Hey Red! Did you get it all figured out. I'm considering yankin' my CA/EPA junk too. I'm a little new to bikes but worked on cars for years. I believe the air going through the reed valves is for the catalyst in the exhaust. Smog pumps on cars pump fresh (unburned) air into the exhaust to supply some of the needed O2 to complete the chemical reaction in the catalytic converter. I think this is the same principal Kawi used the reed valves (check valve instead of smog pump). Since the vaccume in the air box is high under full throttle the valves close. Under decel the carbs close and the vaccume in the air box is low and the air flows to the exhaust (this is when it pops right?). Since not much of this happens under accel I think your calibrations should not be affected.

Like I said, I'm a little new to bikes and I want to learn so anyone please correct me if this is wrong!

[red]

Well, I'm not too understanding on the smog pumps on cars, but I did get it all figured out on the Rex. The shop manual has a diagram of the evaporative system showing direction of fuel and air. Asked alot of questions from ZRXOA members who helped me out alot. Didn't change the way the Rex runs at all, but it did clean the undertank area quite a bit and it doesn't pop as much on decel. The process removed alot of parts all the way to the tail as well. I keep it all in a container (just in case). Hopefully I won't need this stuff anymore, 'cause it will be a bitch putting it all back on. Went with the Muzzys block off plates, which look really sweet. If you decide to go for it and have any questions, let me know.:thumbs:
I'll move on to carb rejetting and exhaust next......good lock

[StrongPerf]

RED

Good Job!:elate: :elate:

I'm glad you got what you wanted out of the effort.

HydroCarbons and CarbonMonoxide are expelled by engines (which are harmful). When extra oxygen is added (via your air box through the reed valves) this helps to make H20 and Carbon Dioxide (which are not harmful). This is a natural chemical reaction but the catalytic converter speeds it up so more of the reaction can happen before it leave your talipipe.

What you did is the same thing we all do to our old muscle cars... Yank the smog pump and lines to clean up the engine bay.

You'll love the jetting and exhaust. I haven't done the exhaust yet but the jetting gave me 2000 rpm deeper toward the redline with much more intensity. My bottem end smothed out with a much better idle. And like Rockon said.. it completely eliminated the decel popping.

Good Luck! I'll look you up when it's time to yank the smog crap.

[red]

You got it, bro....:thumbs:

[dave333]

Originally posted by StrongPerf
When extra oxygen is added (via your air box through the reed valves) this helps to make H20 and Carbon Dioxide (which are not harmful).


How much "extra oxygen" is coming from inside the crankcase? Me thinks not much.

imho, this is more of a ploy to reduce the foul, harmful, volatile crankcase gasses that would have been released into the atmosphere by burning them in the combustion process...

For LOUD popping / nearly backfiring on decel, turn your air/fuel screws out 1/2 turn. If that remedies it, cool. If not, turn out an additional 1/2 turn. I always like to run the screws in before I start messing around so I know where to put it back to in case my results are worse than when I started fooling around. Dig?

For gurgling / light popping on decel, leave it alone. Your bike is tuned a hair lean which is good and makes more power. I like a slight gurgle on decel on my 141hp ZRX, it gives me an audible sign I'm not running fat on the low end...

[Neggy]

Did I read that the Teds Advancer ( great bang for the buck mod) eleviates the pop pop pop on decell ?

[dave333]

No, I never read that. The advancer adjusts timing, not air/fuel mixture. Popping on decel is due to a lean pilot circuit.

[rockon1]

How much "extra oxygen" is coming from inside the crankcase?


Probably as much as anywhere else,however thats mute,clean air system gets its oxygen from airbox.Yeah,while crankcase vents into airbox that doesnt mean clean air system is getting 100% of that ,actually probably very little,as most of that gets sucked into carbs...

[dave333]

Originally posted by rockon1
Probably as much as anywhere else,however thats mute...


moot. That is a moot point


May I differ with that opinion? The hot nasty air in the crankcase would not be able to hold as much o2 as the cooler air outside the crankcase...

[rockon1]

I stand corrected its "moot".:doh Anyways I doubt much of that (crankcase) gets sucked up by clean air system.

[Desertsky]

Originally posted by rockon1
I stand corrected its "moot".:doh Anyways I doubt much of that (crankcase) gets sucked up by clean air system.

I would tend to agree as your engine is sucking in gallons of fresh air while the throttle is open but there is (or SHOULD BE) very little blow by gasses. Also, when the fresh air system is in operation, the crankcase would be under less pressure (or even a vacuum) because you are at higher RPMS and closed throttle.

As a side note, air pumps predate catalytic convertors. I used to run Datsun 510s in the early days and the only year they DIDN'T have the pump was 1972. Even the 1969 models had the pump. No catalytic convertors until 1974 (IIRC)

[waterd0g]

Is it really necessary to remove all the smog junk? I am no fan of tree hugger equipment, but wouldnt it just be easier to jam some plugs into the hoses that go to the reed valve cover plates?

I dont know what all this smog junk looks like, as I have not removed my gas tank yet. but I cant even see under the tank so why do these block off plate mods "LOOK GREAT"?????

I cant see anything up under there at all (with the tank on), so whats the big deal of how it looks?
And since I cant see any smog junk to begin with how does it look better after its all removed and plugged and stuffed or what ever?

later,
rich betz

[waterd0g]

What the hell is with the "KICK ME!" under my name when I post a reply??

Am I a bad speller or what??

What the Hell????

:knock: :knock: :knock:

[DynamicV]

Originally posted by waterd0g
Is it really necessary to remove all the smog junk? I am no fan of tree hugger equipment, but wouldnt it just be easier to jam some plugs into the hoses that go to the reed valve cover plates?


Removal is not necessary and Holeshot's "stage II" kit provides a crossover pipe that plugs the inlets together...similar to what you've described.

Originally posted by waterd0g
I dont know what all this smog junk looks like, as I have not removed my gas tank yet. but I cant even see under the tank so why do these block off plate mods "LOOK GREAT"?????


I feel better knowing that if anyone sees my girl without her coveralls it's all neet under there. On the practical side; when it's time for a valve adjustment I don't have to remove the stuff to get at the valve cover, just one (more) thing I don't have to work around.

Originally posted by waterd0g
I cant see anything up under there at all (with the tank on), so whats the big deal of how it looks?
And since I cant see any smog junk to begin with how does it look better after its all removed and plugged and stuffed or what ever?


It's a personal decision, do as you see fit.

Originally posted by waterd0g
What the hell is with the "KICK ME!" under my name when I post a reply??
Am I a bad speller or what??
What the Hell????

Lighten up, this is an old thread.





























:slap:




:stpoke: :laff:

[Mad Irish]

Originally posted by waterd0g
What the hell is with the "KICK ME!" under my name when I post a reply??

Am I a bad speller or what??

What the Hell????

:knock: :knock: :knock:

Cause you're a newbie
now you are a bruce soon to be a rexer soon to be a hooligan. Its based on your post count

[waterd0g]

Jdunphy,

OK.....that makes sense, but who da hell is bruce??

where do you ride in ohio? I venture into the east coast of ohio quite often and usually end up in or near cleveburg. I lived there for 4 years and for some dumb reason I still have an attraction for the place.

The roads I have traveled aren't exactly deals gap, but they have a few twisties. You want some crappy roads, come over here to pennsyltucky.............

later,
rich

[Dr D]

Hey Fellas,

Quick ?.... What about the vent hoses on the gas tank/carbs? Should those be blocked off? lemme know...

Later On.
The Dr.

[Dr D]

Bike won't start after removal :clint: of all my smog crap:doh I'm thinking that it has a lot to do w/ vacuum hoses not being plugged. Forward me ur thoughts...:thumbs:

[Desertsky]

Originally posted by Dr D
Bike won't start after removal :clint: of all my smog crap:doh I'm thinking that it has a lot to do w/ vacuum hoses not being plugged. Forward me ur thoughts...:thumbs:

There are a couple of spots that need to be plugged after removal of the smog stff. The important ones are the nipples on the carbs. There is one line that goes from the #2 carb to the petcock. That one has to remain. The other three nipples on the carbs have to be blocked. You can use short pieces of hose with screws in them or fo to a carb shop and get dedicated rubber plugs. If you retained the stock airbox, you should also plug the hole where the filtered air came from for the air injector system.

[Dr D]

:thumbs: Thanks for the info... I will double chk my work and hoses as well... Thanks again...

The Dr.

[neverendingmods]

Originally posted by rockon1
Probably as much as anywhere else,however thats mute,clean air system gets its oxygen from airbox.Yeah,while crankcase vents into airbox that doesnt mean clean air system is getting 100% of that ,actually probably very little,as most of that gets sucked into carbs...

What about taking the crank vent line and mating it to the reed blocks. Just eliminating both the crank vent and reed vent to airbox and joining the two? So rather than blocking off the vacuum, you use the vacuum to depressurize the crank. Was under the impression this adds hp. while slightly eliminating popping. Major downside is if motor ever lets go, oil all through exhaust and anybody behind you. Worked on the early 90's Kaws and Suzukis. Anyone try this setup? My bro in law and his buddy just hit me w/ this one over the weekend. Swear by it. I'm nibbling on the hook.:ytrap:

[paulzrx]

I also vent my oil fill cap.....Tapped it ,put a 1/8" fitting and a peice of s/s line to run up under the tank.........Take off your filler cap when engine is running and feel all the pressure coming out....Being a dragbike racer we vent the motors as much as possible........JMO....
Paul.......

[dimora]

Originally posted by waterd0g
Jdunphy,

OK.....that makes sense, but who da hell is bruce??

where do you ride in ohio? I venture into the east coast of ohio quite often and usually end up in or near cleveburg. I lived there for 4 years and for some dumb reason I still have an attraction for the place.

The roads I have traveled aren't exactly deals gap, but they have a few twisties. You want some crappy roads, come over here to pennsyltucky.............

later,
rich

Dude, don't be asking about the Bruce thing...it will go away. You don't wanna know. If you insist, send a PM to ChuckC, he knows how to fix it all up.

Welcome to the Rex board.:howard: