Author Topic: Blow-By Gas/Breather Case  (Read 970 times)

Offline Eldrick

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Blow-By Gas/Breather Case
« on: May 19, 2022, 06:03:46 PM »
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In this image,  fig.1.1 the part [2] 'Breather Case'should be below my Air box. I dont have that, there is just a wee hole, one that is too small for the hose coming out of the top of the engine block. I am using a hose with 11mm Inside diameter  x 16.5mm Outside diameter for the part marked [1] Breather Tube, in the diagram.

Question;
Is the part available anywhere?
Should I care that I otherwise vent to the atmosphere?
Could I fabricate one for a 'yoghurt pot' so to speak and achive the designed effect?
 
1975 Honda CB400f - Red

Offline McCabe-Thiele (Ted)

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Re: Blow-By Gas/Breather Case
« Reply #1 on: May 19, 2022, 06:36:55 PM »
I have one if it's the plastic part that fits underneath held in place by a screw from the inside?
If you PM me your e-Mail I'll send a photo.
« Last Edit: May 19, 2022, 07:57:18 PM by McCabe-Thiele (Ted) »
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Online K2-K6

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Re: Blow-By Gas/Breather Case
« Reply #2 on: May 20, 2022, 08:28:19 AM »
"Should I care that I otherwise vent to the atmosphere?"

Obviously part of original (not sure all specification had it) but don't feel a problem in venting to atmosphere really.

Originally for areas like California in strict emmisions, unlikely one of these engine in good condition has anything much in the way of significant output to concern even the most critical.

Offline Oddjob

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Re: Blow-By Gas/Breather Case
« Reply #3 on: May 20, 2022, 01:50:56 PM »
Most people used to vent to atmosphere, even back when it was available, they'd position the tube over the drive chain so any oil emitted got dropped onto the chain, killed 2 birds with one stone, so to speak.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline TrickyMicky

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Re: Blow-By Gas/Breather Case
« Reply #4 on: May 20, 2022, 02:32:57 PM »
Most people used to vent to atmosphere, even back when it was available, they'd position the tube over the drive chain so any oil emitted got dropped onto the chain, killed 2 birds with one stone, so to speak.
Also, as well as lubing the chain, it kept the air filter in semi-decent condition for a little longer.  Fond memories of production race bikes that had the breather tube extended all the way to the rear number plate to clear the rear tyre. Used to be quite amusing seeing them all sitting there gently fuming away once they were hot.

Offline Oddjob

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Re: Blow-By Gas/Breather Case
« Reply #5 on: May 20, 2022, 02:39:07 PM »
However, I must add, if not using the recycling setup, use a cb500 air filter, as the hole left by not using the setup in the original filter allows unfiltered air to pass into the engine. Or just cover the hole with some tape if it's new.
Kids in a the back seat cause accidents.
Accidents in the back seat cause kids.

Offline Eldrick

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Re: Blow-By Gas/Breather Case
« Reply #6 on: May 21, 2022, 08:55:40 AM »
Found a Breather Chamber on e-bay for under £20. So I will instal that. I like the idea of having another genuine part on the bike. If I am super clever I will see if I can copy the design into 'blender' and maybe have it 'printed'.
1975 Honda CB400f - Red

 

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