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Murray,
I think he is talking about the american bikes in the pictures...........Most of the North American CX's have venting through the heads and not where your arrow is pointing
 

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You're going to need some kind of vent for the crankcase. The ones that vent through the head are not enough and is why the breather bottle is an upgrade.
 

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Discussion Starter #6
a1mod.jpg Yes i'm asking about removing a bottle breather.
My CX500C 81 is production for the European market.
On attachment my engine but i think that honda have made this part....... probably it is necessary for regular engine functions.
I have think to remove origial tube and appli a little filter...what do you think ??
 

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It will spray oil mist so yes a filter of some sort will be needed.
 

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honda never built it that way for any market there never was a bottle breather only on any engine

post your engine number and frame number

i bet its a gl500 or 1982 cx500 motor in a cx frame using the cdi rear cover that is original

you wont have enough venting
 

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here the bottle breather was a update/refit never ever factory fitted

i posted this a hundred years ago but found this reprint here

http://cx500forum.com/forum/technical-help-forum/2355-crankcase-breather-mod-4.html
Hi MGR1,



To the best of my knowledge the CX500s with the 'SHADOW' decal on the sidecover were only sold in Australia and New Zealand between 1980 and 1982 (our '78 and '79 models didn't have the 'SHADOW' decal on the sidecover).



I've found some more technical information on the breather modification:



Crankcase breather pipe modification – 1980 CX500



1. A modified crankcase breather system has been introduced on the 1980 CX500 and retro-fitted to the earlier models.



2. It was found that when the engine speed was increased above 7000 RPM, excess oil was being blown out of the breather tubes fixed to each cylinder head and accumulating in the air filter box. To rectify this, Honda introduced a new crankcase breather system, whereby the timing inspection plug doubles as an engine breather.



3. In the event of the modified assembly not being fitted. The following parts can be obtained from an authorized Honda dealer.

Cylinder head plug (2 off): 90547-415-305

Timing inspection breather plug: 12361-415-610

O-ring: 91302-001-000

Breather tube: 95005-12460-20



4. Dismantle the previous breather assembly. Use the two plugs contained in the kit to blank off the cylinder head nozzles and secure with the wire clips used to retain the previous pipes. Fit the new inspection plug to the timing hole and run the breather pipe from the top of the plug to the pipe joint at the base of the air filter box.




This image has been resized. Click this bar to view the full image. The original image is sized 800x600.













 

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Discussion Starter #11
You think that little filter is a bad idea ?
my frame number is 2201794 and is a 81 made
it is marked on document PC01-E
tomorrow i can post engine number...
 

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81 cx cdi models in Europe came with the bottle breather factory fitted there was no other breather fitted,where the earlier models had the head breathers it was just a blank casting with no steel inserts. Engine numbers with the bottle breather fitted started at 220. PC01-E 220 would be an 81 CX 500 Cb custom.
You can fit a filter to the top of the bottle breather just don't wear any light colored pants and you do get more engine noise !
 

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never seen one fitted from the factory

they told us here it was to add breathing for hogh speed running

and we installed them on gl500 gl650s and connected it to the existing

tube going to the breather with a t from the rear cover port
 

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Yes here too Murray it first was a dealer mod for earlier bikes with the head breathers but then from 81 they stopped the head breathers altogether on cdi bikes and came with the bottle factory fitted.
 

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that does not make any sense with the road road speeds over here (70-80 mph) the gl500 would puke out the front cover gasket without the bottle breather added

it could not vent properly on just the rear pulse generator cover
 

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Yes here too Murray it first was a dealer mod for earlier bikes with the head breathers but then from 81 they stopped the head breathers altogether on cdi bikes and came with the bottle factory fitted.
Yes, 1981 'B' models (standard, like mine, and also the custom) had the crankcase breather only and no head breathers.
 

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Not to be contrary.....but my '81 CXC is stock. The ccase breather is from the heads to the air box. Timing inspection cover is just like the cover over the cshaft on the front of the engine. I believe mine was a US model, don't know if the European models are different.
 
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