A Dissertation On Ventilation - Page 3 - Kawasaki KLR 650 Forum
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post #21 of 77 Old 11-01-2013, 08:40 PM
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Quote:
Originally Posted by twinjet View Post
Bruce Meyer, a Ducati tuner, had a race modded Ducati 996 with an air oil separator under the seat. Adventure bikes like the KLF could put the separator in a top case!
twinjet,
Too complicated/messy for me.

The KL what? Ya been riding too many 4 wheelers!

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post #22 of 77 Old 11-01-2013, 11:22 PM
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twinjet,
Too complicated/messy for me.

The KL what? Ya been riding too many 4 wheelers!
KLF? That's it, no more posting from work.
And, definitely messy but, a top case could hold and separate a lot of oil vapor.

Seriously and to come back to topic, the mod to the PCV mod I want to try is to leave out the PCV valve and to remove the stock case breather tube from the airbox. I just don't like recycling oil fumes from the case into the intake.
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post #23 of 77 Old 11-07-2013, 06:04 PM
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Twinjet,
Lots of riders install a K&N or Uni-filter onto the crankcase vent hose.

BUT, That actually Does Very Little, if anything to Aid Positive crankcase ventilation.

And DON'T ride into TOO deep of a water hole.

pdwestman
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post #24 of 77 Old 11-07-2013, 07:00 PM Thread Starter
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Quote:
Originally Posted by twinjet View Post
Seriously and to come back to topic, the mod to the PCV mod I want to try is to leave out the PCV valve and to remove the stock case breather tube from the airbox. I just don't like recycling oil fumes from the case into the intake.
Alas, you harken back to the "bad old days," twinjet (pre-1962), when U-shaped dump tubes vented automobile crankcases to the atmosphere!

I hear your objection to recycling crankcase aerosols into the engine, but . . . how do you reconcile the ubiquitous and universal emissions reduction, pollution control, crankcase ventilation systems on every street-legal automobile and truck in the US today? Systems required by LAW?

I'd guess you're no fonder of the positive crankcase ventilation system on your car, than the "re-breathing" crankcase ventilation system on your KLR.

Regardless, interesting discussion on this thread from all posters!

Yet, no one has addressed the issue I attempted to raise in my initial post . . . ventilating the crankcase through the intake manifold; using intake manifold vacuum to evacuate and to lower crankcase air pressure . . . just another speculative concept whose time obviously has yet to come . . .
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post #25 of 77 Old 11-07-2013, 07:40 PM
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Damocles,
WE are Waiting, For You, To BE, the first to Figure OUT, HOW to do it correctly!
I gave you my suggestion. Put it to practice, You started this thread.

You should have been prepared to Finish It!

pdwestman
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post #26 of 77 Old 11-07-2013, 09:34 PM
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Originally Posted by Damocles View Post
Alas, you harken back to the "bad old days," twinjet (pre-1962), when U-shaped dump tubes vented automobile crankcases to the atmosphere!

I hear your objection to recycling crankcase aerosols into the engine, but . . . how do you reconcile the ubiquitous and universal emissions reduction, pollution control, crankcase ventilation systems on every street-legal automobile and truck in the US today? Systems required by LAW?

I'd guess you're no fonder of the positive crankcase ventilation system on your car, than the "re-breathing" crankcase ventilation system on your KLR.

Regardless, interesting discussion on this thread from all posters!

Yet, no one has addressed the issue I attempted to raise in my initial post . . . ventilating the crankcase through the intake manifold; using intake manifold vacuum to evacuate and to lower crankcase air pressure . . . just another speculative concept whose time obviously has yet to come . . .
Yes, I am guilty on all counts. In my opinion forcing an engine to breathe it's own fumes is akin to forcing a person to breath their own fumes. But to address your original question, since in a healthy KLR there shouldn't be a lot of case pressure and breather flow produced, connecting the breather downstream of the slide and throttle plate should do the job you describe. At idle and the small throttle openings that riders use most of the time, intake manifold vacuum should be sufficient to draw blow-by fumes into the engine.
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post #27 of 77 Old 11-07-2013, 09:43 PM
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Originally Posted by pdwestman View Post
Twinjet,
Lots of riders install a K&N or Uni-filter onto the crankcase vent hose.

BUT, That actually Does Very Little, if anything to Aid Positive crankcase ventilation.

And DON'T ride into TOO deep of a water hole.
Yup, I just want to reduce pumping loses by eliminating the restriction where the case vent hose goes into the airbox and stop feeding fumes to the intake. Now if I could find a way past the airbox so the hose can be extended above the high tide mark. (Which in my case can happen when the bike is horizontal.)
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post #28 of 77 Old 11-08-2013, 05:53 AM
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Quote:
Originally Posted by twinjet View Post
At idle and the small throttle openings that riders use most of the time, intake manifold vacuum should be sufficient to draw blow-by fumes into the engine.
Quote:
Originally Posted by Damocles View Post
Yet, no one has addressed the issue I attempted to raise in my initial post . . . ventilating the crankcase through the intake manifold; using intake manifold vacuum to evacuate and to lower crankcase air pressure . . . just another speculative concept whose time obviously has yet to come . . .
Would this not create a huge vacuum leak rendering the vacuum operated slide diaphragm in the carb useless among other problems?

Gray-haired riders dont get that way from pure luck.

Unknown
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post #29 of 77 Old 11-08-2013, 06:42 AM Thread Starter
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Would this not create a huge vacuum leak rendering the vacuum operated slide diaphragm in the carb useless among other problems?
I don't think so; already, vacuum ports operate the petcock, and, on later and California model KLR650s, some sort of pollution control mechanisms.

With air flow through the venturi, "vacuum" (pressure differential) should be available for CV carburetor operation (or else, Bernoulli was just funnin' us). Some sizing adjustment regarding jetting, profiling of needle, slide spring strength, etc., might be in order if any great flow occurs from crankcase to intake manifold, but . . . I'd imagine the flow minimal, for an engine in good condition.

I'd envision the crankcase vent line connection at the intake manifold much smaller in cross-section than the venturi; thus of minor consequence regarding the resulting dynamic vacuum.

Many carbureted automobile engines connect their crankcase ventilation lines to the intake manifold, yet retain enough vacuum for fuel flow. Don't know of any CV engines so rigged, but imagine enough pressure differential exists to exercise the diaphragm and slide mechanism.
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post #30 of 77 Old 11-08-2013, 08:19 AM
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Originally Posted by Damocles View Post
I don't think so; already, vacuum ports operate the petcock, and, on later and California model KLR650s, some sort of pollution control mechanisms.

With air flow through the venturi, "vacuum" (pressure differential) should be available for CV carburetor operation (or else, Bernoulli was just funnin' us). Some sizing adjustment regarding jetting, profiling of needle, slide spring strength, etc., might be in order if any great flow occurs from crankcase to intake manifold, but . . . I'd imagine the flow minimal, for an engine in good condition.

I'd envision the crankcase vent line connection at the intake manifold much smaller in cross-section than the venturi; thus of minor consequence regarding the resulting dynamic vacuum.

Many carbureted automobile engines connect their crankcase ventilation lines to the intake manifold, yet retain enough vacuum for fuel flow. Don't know of any CV engines so rigged, but imagine enough pressure differential exists to exercise the diaphragm and slide mechanism.
I think we're on the right track now. An inline orifice like a carb jet could be used as a restriction if vent line flow causes too much of a vacuum drop. The only roadblock left to this experiment I can see now is finding a place in the intake tract to put the vent line. Most of the easily reached intake tract is the rubber boot connecting the carb to the head.
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