Crankcase Scavenging

[Anonymous]

you still have me concerned about how it is reducing your HP, if your engine is flowing oil properly you wont get any through your valve cover vent hole. if you have a clog in the drain return somewhere then I can see how the oil can be pulled through. on a proper running engine the PCV system design can not reduce your HP levels. if you have lots of oil slop then yes the PCV system will contaminate your intake charge with another petroleum product and thus will raise the octane level of your fuel, but still uncertain on how it will lose HP.

[scotty]

I've been thinking of using my other 3 vacum ports on my carbs and connect them to a single hose to the top of the valve cover breather. The fourth port goes to my petcock. Should be OK as long as there is not much blowby. Once there is a negative pressure in the engine it should'nt affect the carbs----I think?.

Jake are you still ising the vacume petcock???

[RacingJake]

Hey Scotty

Yeap, I'm using the number 1 carb (38CV's) to operate the fuel petcock.

Long time no hear?

[Anonymous]

you still have me concerned about how it is reducing your HP, if your engine is flowing oil properly you wont get any through your valve cover vent hole. if you have a clog in the drain return somewhere then I can see how the oil can be pulled through. on a proper running engine the PCV system design can not reduce your HP levels. if you have lots of oil slop then yes the PCV system will contaminate your intake charge with another petroleum product and thus will raise the octane level of your fuel, but still uncertain on how it will lose HP.

HP reduction isn't necessarilly from pulling oil. What you are injecting into the carbs is blowby. The oxygen content is much lower than the clean air you are replacing. Less oxygen = less hp.

[gsbill]

Don,

Your cam chain slings oil right below that valve cover vent. Oil does make its way into that vent hose. Your crankcase gets" presureized as the piston go down, helping push that slung oil thru the vent hose... Any blow by will be in the crankcase as pressure, and will vent thru the valve cover...

Big high HP motors(PSB motors) use GM vaccum pumps to suck any built pressure out of the crank case..The word is, its worth about 15 horsepower...Keep in mind this is on a 25k plus, 300hp motor.

PCV is on cars to control emissions....When ya hop up a car, the first things to go are the emissions junk..Why suck hot, polluted, oxygen depleted air into a motor you re trying to make power with..

Jake,

Your idea is correct in theory, but it wont work the way you want...Skip it! It will cause you problems. Good Luck! Bill

[Anonymous]

ahh yes forgot about the cam chain being right in the path of the vent tube.
although there are still street legal cars with very impressive HP numbers that still contain the emissions equipment.
I like to think outside the box a lot

[scotty]

Hey Scotty

Yeap, I'm using the number 1 carb (38CV's) to operate the fuel petcock.

Long time no hear?

I was wondering if the stock valve supplies enough fuel when you are wide open??

My bike is on the lift for weeks Jake. I started to change the timing chain and mess with the valves but i had the accident with the kZ1300 in the interim. I am also having a 6' wide double door installed on my recently extended Florida room so i can roll all the bikes inside and still have room to move around. Last week i ran across a 5X8.5 foot enclosed trailer that looks like new.
Well i have to wrap up all these loose ends so I can get back to living again.
What i was getting at was that the stock cams have a bit of a ridge on them so i have decided to replace them. I am wondering if the followers will show wear to the point of needing replacement.
Thats the ball of wax Jake.

[RacingJake]

I was wondering if the stock valve supplies enough fuel when you are wide open??

That's a good question, when doing a static it flows great...... under load??

As for rockers I don't know, maybe a shop can check them.

Hope your're doing OK

[scotty]

I was wondering if the stock valve supplies enough fuel when you are wide open??

That's a good question, when doing a static it flows great...... under load??

As for rockers I don't know, maybe a shop can check them.

Hope your're doing OK

i fine jake. just keep that sportster locked up in case i find out where you live
Im ticked though because i was drooling over a special head complete which Murdoch racing was going to build for me and i have spent so much $$ on the other crap. well that's life

Looks like i dont get any head 8O hmmm

[Hap Call]

I've run the crankcase vent to a small handmade manifold that is attached to my four pod filters. I cannot tell any drop in horsepower. The amount of air that is being pulled into the carbs is so much greater than the small amount coming out of the case it really makes no difference. Remember that the crankcase hose went to the air box when Suzuki made the bike 20+ years ago.

The reason I did it was I got tired of all the oil that found its' way onto my bike due to the little hole that was necessary for the oil collection bottle. Over a period of a couple of months the rear of the bike was covered in a layer of Mobil Synth oil.


Hap

[gsbill]

I have not seen or heard of anyone in over 30 years of messing with bikes, who, by trying to enhance performance, has routed crankcase gases back into the engine...BTW..if you had that much oil coming out of your breather, something is/was wrong....There ya have it Jake....Obviously 2 completely opposite positions to choose from!!

Let us know which you choose and how it works.

[RacingJake]

Thanks guys for the info.

I'd really like to run it to the exhaust cause last year while the bike was idling i placed a red rag at the end of the V&H and it was sucked into the the pipe then blown out. Looked cool going back and forth all by itself.

So do I still need a catch can if I run it to the exhaust?

[Hap Call]

BTW..if you had that much oil coming out of your breather, something is/was wrong....

Wrong. Any gases coming out of the case will have vaporized oil in it. If you have ever seen a drop oil hit water and spread over a large area you would understand. I said a thin layer of oil over a period of a couple of months...it was not dripping off the bike.

In my 30 years of working on bikes I have seen every manufacturer route the crankcase gases into the air box. I will agree that it's not a performance modification but it is a living-with-day-to-day modification.

Hap

[gsbill]

WTF?

Hap.... I said a thin layer of oil over a period of a couple of months...it was not dripping off the bike.

Hap...Over a period of a couple of months the rear of the bike was covered in a layer of Mobil Synthoil.

If your bike is covered in a layer of oil, something is wrong.. Your words not mine....Find me one person that figures a bike covered with a thin layer of oil is OK, or "right" as we're on right & wrong here.

I'm trying to help Jake go quicker...We're not on a day to day thread here. Jakes wants to go racing! I had 2 vents on my 1150 and NEVER had an oil film anywhere on the bike, either with a catch can or without one..

Have a wonderful 4th of July!

[Hap Call]

WTF?

Hap.... I said a thin layer of oil over a period of a couple of months...it was not dripping off the bike.

Hap...Over a period of a couple of months the rear of the bike was covered in a layer of Mobil Synthoil.

If your bike is covered in a layer of oil, something is wrong.. Your words not mine....Find me one person that figures a bike covered with a thin layer of oil is OK, or "right" as we're on right & wrong here.

I'm trying to help Jake go quicker...We're not on a day to day thread here. Jakes wants to go racing! I had 2 vents on my 1150 and NEVER had an oil film anywhere on the bike, either with a catch can or without one..

Have a wonderful 4th of July!

Yeah...WTF!

When you have hot air containing oil and water vapor when it exiting an engine it will start to condense on a cooler surface. When you use a catch bottle you use the inner surface of the bottle as the cooler surface to condense the MAJORITY of the vapor into a liquid. The vent hole is put in there to allow the continuous flow of air/vapor mixture out of the engine. As it flows out it carries oil and water vapor that did not condense in to bottle. It will and can condense on the cooler surface of your frame if it comes into contact with it. I don't care if you've had a dozen vents on your 1150, if some crankcase gases are passing through them they are carring oil with them. Period. It's called physics...get use to it.

You are correct in say that the pistons going down causes pressure in the cases but did you forgot about the other two pistons that are traveling up at the same time creating a opposing vacuum...wait that dosen't make sense!!!?? how can that be??? Again, physics. WTF.

What causes pressure in the crankcase? Piston blow-by and valve guides leaking. Every engine has some blow-by because there is no such thing as a perfectly sealed combustion chamber on a piston engine, thus every engine has some positive crankcase pressure. WTF

As far as the cam chain slinging oil into the vent hole did you forget that there is a oil collection chamber, then a gasket with only two small holes, and finally the vent hole? Oh, I'm sure that the slinging force of the chain and the pumping of the pistons are pushing the oil out. Yeah, right.

You obviously have a greater control of the laws of physics than other mortal men.


If Jake is going for 1/4 mile times then he should just put a crankcase filter on the vent off the top of his engine. That will prevent garbage from being pulled into the engine as it cools down.

I ride my bike thousands of miles a year, have rebuilt the engine four times, have put over 250,000 miles on it since I bought it off the showroom floor and you believe you know that something is wrong with my bike? You're not as bright as you think. Averaging 60 miles a day at 75 to 80 miles an hour will cause oil vapor to pass through a collector bottle and into the atmosphere where some will deposit on the rear of the bike. I know why that happens..you don't.

WTF my a$$.

Happy 4th of July

Hap