Case vent gases

[81xsproject]

So, I am getting ready to do TC's PVC velocity stack mod and I thought, 'hey, I could port in the crank case vent gases into the stacks to reburn that crap.' But then I remembered that on the stock setup the gases come in BEFORE the filter and my idea would be AFTER.

Would this be okay? I don't see anything but particulate being able to make it up the tube...

[skids]

I'll bet that officials from the state of California are looking for you right now just for thinking about a mod! Actually I believe that the stock intake comes into the center of the air filter and that plactic crank-case-breather manifold is inside of the box, but is down stream of the filter. Personally, I think that routing nasty stuff into finicky carbs is a bad idea. Dirty oily air from the crankcase tube can't help the slides, can they? Sticking slides mean air polution...or at least thats my story and I am sticking to it.

[79XS11F]

Thats right.. Those hoses that go to the air box are not filtered. In your air box the air input gos into the center of the air filter. In any case if there solids in that vent pipe your already in a world of hurt. Now ... do keep in mind that a back fire (the real thing where flames come out the input side of your carbs) could be interesting if there's flammable fumes in the crank case :-)
Rob

[TopCatGr58]

Hey Jessie,

I would think that you could first put a FILTER(ie. PCV type) in line on the hose going to the intakes, and THEN plug it into the intake/velocity stack(s)! I'd suggest getting a clear one that you could inspect quickly so you would know when you might need to replace it before it gets clogged!? JAT!
T.C.

[Crazcnuk]

the only thing those hoses are for is to vent unburnt fuel out of the crankcase into the carbs. THis will not bother, or gum up the carbs.

The trick is to have the hose set up in such a way that any oil that may come out is trapped before it can get sucked in.

Since the XS 11 engine is very efficient I doubt there are enough gases in the crankcase to worry about reburning. Most engines throw a large part of thier fuel out the exhaust or past the rings, but any engine that produces nearly 1.5hp/cuin, is not leaving much fuel unburnt, assuming it's in decent tune.

[mason79]

for the short time i had pods, i wrap a piece of t shirt in lieu of buying a fancy filter; over the vent tube, it was very oily, i guess all than pressure and splashing around vaporizes some oil, i got tired of looking at it, lame, that's why i like stock, a closed system
positive crankcase ventitillating.

[pggg]

Recycled hot air sucks energy from the bike, cold air thru the carbs is way better, more oxygen, a tube with sponge rubber inside jammed down the crankhose does the trick, the motor should be running clean and clear anyway, no fumes or smoke, if not the motors knackered or on its way out, worn rings valves and stuff probably, that's the pollution, that spider thing in the airbox, it grunges up with soapy looking oil, as well as belching hot crankcase air thru the carbs, I ditched the thing long ago, get a bigger airbox volume too, any pollution control claims are dubious, talkin' miniscule ppm differences, I don't feel guilty, soon old air-cooled motors will be illegal anyway, better use the bike while you still can...

[mason79]

illeagal where?

[BrianB]

soon old air-cooled motors will be illegal

You gota be kiddin. I'll ride my bike till they pry it from my dead cold fingers.

And what about my RC plane engines, and my Lawnmower. Oh heck I guess no more yard work. I am trying to imagine a water cooled push mower.

[mason79]

then i guess they'll have to outlaw lawnmowers and blowers, maybe we should design water cooled units for the new market and get wealthy!!

[Crazcnuk]

Unless liquid cooled engines get to the 1.5hp/cuin range, the air cooled ones have nothing to fear.

Almost all of the emission controls out there are designed to pick up and get rid of unused fuel.

EGR Recirculates a portion of the exhaust, to burn the fuel that didn't burn the first time

PCV Draws the air in the crancase through the carbs to burn any fuel that may have snuck past the rings.

FES

[Crazcnuk]

Reposted because of the stupid 10 min limit on edits AND the fact that TAB doesn't work properly here! (oh and neither do the smilies that insist on going only at the end of the message...)

Unless liquid cooled engines get to the 1.5hp/cuin range, the air cooled ones have nothing to fear.

Almost all of the emission controls out there are designed to pick up and get rid of unused fuel.

EGR Recirculates a portion of the exhaust, to burn the fuel that didn't burn the first time

PCV Draws the air in the crancase through the carbs to burn any fuel that may have snuck past the rings.

FES Draws fumes from the fuel tank instead of letting them out into the atmosphere

Air Injection Puts air into the exhaust to burn the same fuel the EGR works on

Catalytic Converter Converts unburned fuel and CO into water and Carbon dioxide


THE best way to do all of these, bar none, is to burn all the fuel the first time. You can tell how efficient your engine is by how much power it produces from the fuel used. Back in 1954 a white paper on the venerable small block chev, we all know and love, stated that, at that time (and technology) all internal combustion gasoline engines should produce at LEAST 1hp/cu in.

If you consider the good old 350 chevy usually produces between 165 and 245hp, you can see they fall way short. All this means unburnt fuel, hence the need for emission controls.

Most hotrods can pass the majority of emission tests w/o using any emission controls, since the point of 'hot-rodding' is to make power, and the best way to do that is to be efficient.

Even normal cars, now, with our better technology should be far more efficient, but in many cases are not. We are starting to see common engines, like my neon, which are 2.0l (123cuin) and 132hp, or slightly better than that.

The XS1100 is 67cuin and 95hp or 1.418hp/cuin. or very efficient by any standard. There will be less unburnt fuel from the XS than most other vehicles on the road.

[TopCatGr58]

Originally posted by Crazcnuk
Reposted because of the stupid 10 min limit on edits AND the fact that TAB doesn't work properly here! (oh and neither do the smilies that insist on going only at the end of the message...)

The XS1100 is 67cuin and 95hp or 1.418hp/cuin. or very efficient by any standard. There will be less unburnt fuel from the XS than most other vehicles on the road.

Hey CrazCnuk,

IF you'll "play" a little with the smilies, you'll see that they are very simple text codes....ie. sad =:sad: , eek=, cool=, several are just a Colon=: and ), o, D, p, and semicolon=;+) respectively= , and a few are longer phrases:
"rolleyes"= ; "confused"= ! All of the ones with words just are bracketed with a colon just before and after the words, no spaces.......so you can type them in anywhere in the text you like.

I think perhaps that PGGG might have been thinking more about what I have heard about the abolishment of 2-stroke machines, which are also usually air cooled, but produce much more unacceptable emissions!?
T.C.

[Pat Kelly]

Bikes in Calif. aren't smog checked.
On my wifes (ex) XS750 I installed an aftermarket airfilter. I used the OEM crankcase tubes from the OEM airbox for the crankcase vent. It was a 1 into 3 tube assembly with no filter in the system. The tubes pointed straight into the carb inlets. Worked fine.

[Crazcnuk]

Heh, thx TC. I only threw that in after I hit tab and accidentaly saved the message part way in, then spent more than ten minutes editing it so it wouldn't go, then tried to add a smiley to show I was only pretending to be perturbed!

As for the 2 strokes, they were, essentially legislated off the road by the mid 70s, although there are still a few around in other parts of the world, or for racing.

I don' t think there is any law against 2 strokes, just they had a hard time meeting the emission standards of the time. I bet someone could overcome that if they put thier mind to it.