Overflow tube issue

[jbfla]

Originally Posted by surfndirt

So from what I've read in this interesting thread... today I removed the OCS and just cut a couple inches off the tube that went to the airbox and connected it to the crankcase. Should be all good, correct?

We shall see.....when the next oil analysis is performed.

Right now it's an experiment with unknown results.

jb

[2LZ]

I think if (when?) I change to a K&N-style pod filter to open up the breathing for the new muffler, I'll remove the whole contraption, run a tube off the crankcase across the motor and off the backside, then put on a small filter on the end of it just to keep any possible junk from being sucked it. That will also let me know how badly it's oozing.

I'm just not a huge fan of running swamp gasses back through what should be a fresh/clean air situation that a possible intake sensor and O2 sensors are sniffing.

[katflap]

The results are in, folks

The bag I used was about 5 - 6 litres ( tested by filling with water)


Test 1,

Idle (1500rpm), Temp range 27c - 65c = 6 mins to fill bag.

Test 2,

Idle (1500rpm), Temp range 80c - 85c = 6 mins to fill bag.


Result,

About 1 litre of blow by gas per minute at idle


I was expecting a little less at the higher temperature.

[2LZ]

katflap blinded me with SCIENCE!! ;-)

That's pumping out some good volume. I wonder what it's like at 5k?

[detours]

And it blows up balloons! Is there anything the RX3 can't do?

[Azhule]

Originally Posted by detours

Is there anything the RX3 can't do?

We found something all of our China Bikes couldn't do the other week remember ride up and down that one way trail/mountain

[BlackBike]

Originally Posted by detours

And it blows up balloons! Is there anything the RX3 can't do?

broke out in laughter...good one

[katflap]

Originally Posted by detours

And it blows up balloons! Is there anything the RX3 can't do?

Great for kids parties and my bike comes with a clown riding it

[katflap]

Originally Posted by 2LZ

katflap blinded me with SCIENCE!! ;-)

That's pumping out some good volume. I wonder what it's like at 5k?

Well as you ask...

This gives me the excuse to quote a little more, "Shed Science"

The formula quoted in the article i linked in a previous post is -

RPM x ENGINE SIZE (in litres) divided by 2
----------------------------------------------------------------------------------
5000 x 0.25 :- 2 = 625 Litres per minute ( volume of air being used by engine)
-----------------------------------------------------------------------------------
"The blow-by rate, is a percentage, which expresses how
much of this air leaks past the piston and into the crankcase. It can only really
be determined through direct measurement but good rule-of-thumb figures are"

0.5% - New engine, after run-in. (0.005)
1% - Design target for breather sizing. (0.01)
2.5% to 3% - Maximum (e.g. for a worn engine, or poor piston ring sealing) (0.025 - 0.03)
---------------------------------------------------------------------------
625 x 0.005 = 3.125 litres per minute
--------------------------------------------------------------------------------
So the answer is about 3 litres per minute @ 5000 rpm on a good engine
Thats about 3/4 of a gallon of by pass gas every minute.
__________________________________________________ _________________________________________
The by pass gas is mainly damp air with a little exhaust gas and fuel.

If the blow by gas contains only 0.25 % of fuel, thats still a teaspoon full of fuel vapour being dumped in to the crankcase every minute.

Ok i'm done waffling on now , going to shut the shed door

[Jay In Milpitas]

Good test, Katflap.

But are those metric, Imperial, or US (inch) minutes?

Regarding the cold vs. warm, on one hand, the oil is thicker when cold and should seal the rings better, yet when warm the piston expands. Then again so does the cylinder block.

Maybe it's all dependent on tire (tyre) pressure?

[katflap]

Originally Posted by Jay In Milpitas

Good test, Katflap.

But are those metric, Imperial, or US (inch) minutes?

Regarding the cold vs. warm, on one hand, the oil is thicker when cold and should seal the rings better, yet when warm the piston expands. Then again so does the cylinder block.

Maybe it's all dependent on tire (tyre) pressure?

I've gone with the wife's, " I'll just be a minute ! " measure of time

Also,
results from a British bin bag and an American garbage bag may differ.

[dpl096]

Well done Kat !

[BlackBike]

When I first saw the bag with liquid i thought, good grief that a lot of condensation.

Good job Kat, they don't call it hydrocarbon for nothing.

[jbfla]

Originally Posted by detours

And it blows up balloons! Is there anything the RX3 can't do?

Tell me that I'm not the only one dumb enough to try this:




But here is what happened, and I need one of you smart guys to explain why.

I attached the balloon to the crankcase vent, and let the engine idle for a minute, then revved the engine a few times.

Nothing happened to the balloon except a bit of fluttering.

When I turned the engine off, the balloon inflated.

jb

[Jay In Milpitas]

Originally Posted by jbfla

Tell me that I'm not the only one dumb enough to try this:




But here is what happened, and I need one of you smart guys to explain why.

I attached the balloon to the crankcase vent, and let the engine idle for a minute, then revved the engine a few times.

Nothing happened to the balloon except a bit of fluttering.

When I turned the engine off, the balloon inflated.

jb

Your foreplay worked, it got aroused.

If the engine was cold when you started the test, then after shut down the residual heat of the metal continued to warm the air inside the cases, causing expansion.